Communication Systems, Popular Questions: ICSE Class 12-science PHYSICS, Physics Part Ii

abhinuj28... asked a question

Subject: Physics, asked on on 11/1/11

what is modulation? what is its need.

Akash Sharma asked a question

Subject: Physics, asked on on 6/10/17

Q.30. Mass is distributed uniformly over a thin square plate. If two end point of a diagonal are (- 2, 0) and (2, 2), what are the coordinates of centre of mass of plate?
(1) (2, 1)
(2) (2, 2)
(3) (1, 0)
(4) (0, 1)

Anandita asked a question

Subject: Physics, asked on on 22/2/11

What is meant by grating element?

Akash Sharma asked a question

Subject: Physics, asked on on 25/10/17

Q.29. A force F is applied at the top of a ring of mass M and radius R placed on a rough horizontal surface as shown in figure. Friction is sufficient to prevent slipping. The friction force acting on the ring is -

(1)

\frac{F}{2}

towards right
(2)

\frac{F}{3}

towards left
(3)

\frac{2 F}{3}

towards right
(4) Zero

Abhiram Sasidhar asked a question

Subject: Physics, asked on on 21/2/13

why skywave not used in the transmission of tv signals?

Diya Mallick asked a question

Subject: Physics, asked on on 13/12/15

what are base band, band width and fading ?

Karan asked a question

Subject: Physics, asked on on 4/3/14

What is the difference between point to point and broadcast communication modes. Give one example

Sky asked a question

Subject: Physics, asked on on 18/1/18

Solve this:
Q.32. If a carved black utensil is heated to high temperature and then brought in dark then :
(1) Both utensil and its carving will shine
(2) Only carving will shine
(3) Only utensil will shine
(4) None of the utensil and carving will shine

Alka Vijay asked a question

Subject: Physics, asked on on 24/2/11

define sky wave propogation

Akash Sharma asked a question

Subject: Physics, asked on on 26/9/17

Q.11. Two rings having same radius and mass are placed such that their centres are at a common point and their planes are perpendicular to each other. Find the moment of inertia of the system about an axis passing through the centre and perpendicular to the plane of one of the rings. (M = mass of each ring and R = radius).

Doctor Ji asked a question

Subject: Physics, asked on on 25/1/19

Please solve it

Sky asked a question

Subject: Physics, asked on on 18/1/18

Solve this:
Two identical bodies are made of a material for which the heat capacity increase with temperature. One of these is at 100^o C, while the other one is 0^o C. If the two bodies are b ought into contact then, assuming no heat loss, the final common temperature is :
(1) less than 50^oC but greater than 0^o C (2) 0^o C
(3) 50^o C (4) more than 50^o C

Mirza Khalit Afzal Beg asked a question

Subject: Physics, asked on on 24/6/12

why ar microwaves used in RADAR?

Akash Sharma asked a question

Subject: Physics, asked on on 25/10/17

Q.4. What should be the minimum coefficient of static friction between the plane and the cylinder, for the cylinder not to slip on an inclined plane -
(1)

\frac{1}{3} \tan θ

(2)

\frac{1}{3} \sin θ

(3)

\frac{2}{3} \tan θ

(4)

\frac{2}{3} \sin θ

Amrutha asked a question

Subject: Physics, asked on on 12/11/12

when modulation index is kept less than 1 distortion dosent occur.......how and why???? plxzzzzzzz reply briefly........nd fastly.......

Akash Sharma asked a question

Subject: Physics, asked on on 26/2/18

Solve this:
Q). A sphere of radius 25 cm and mass 1 kg is hung by a string of negligible mass and length 40 cm, then tension in the string is :

(1) 10.81 N
(2) 18.4 N
(3) 10 N
(4) 8 N

Aditi Singh asked a question

Subject: Physics, asked on on 22/11/14

draw a block diagram of a simple amplitude modulation.explain briefly,how amplitude modulationis achieved.

Sky asked a question

Subject: Physics, asked on on 18/1/18

Solve this:

Q. Two spheres of radii in the ratio 1 : 2 and densities in the ratio 2: 1 and of same specific heat, are heated to same temperature and left in the same surrounding. Their rate of falling temperature will be in the ratio:

(1) 2 : 1 (2) 1 : 1 (3) 1 : 2 (4) 1 : 4

Armin Kalita asked a question

Subject: Physics, asked on on 1/3/12

Explain why high frequency carrier waves are needed for effective transmission of signals?

Akash Sharma asked a question

Subject: Physics, asked on on 18/9/17

Q The only force F acting on a 2 kg body moves along x-axis varies as shown in the figure. The velocity of the body along positive x-axis at x=0 is 4m/s. The kinetic energy of the body at x=3 m is:-
1) 4 J
2)8 J

3)12 J
4)16 J

anupgoyaledurtc... asked a question

Subject: Physics, asked on on 6/12/10

what is square law device? what is the function of this?

Please suggest me any me hurry up!

i am wating your reply?

Rocky asked a question

Subject: Physics, asked on on 10/10/17

Answer question 10 given in the photo in a careful manner.

Jayshree asked a question

Subject: Physics, asked on on 13/1/13

State two factors by which the range of TV signal can be increased??

Sky asked a question

Subject: Physics, asked on on 18/1/18

Solve this:
Q). Two thermometers are used to record the temperature of a room. If the bulb of one is wrapped in wet hanky
(1) the temperature recorded by both will be same
(2) the temperature recorded by wet-bulb thermometer will be greater than that recorded by the other
(3) the temperature recorded by dry bulb thermometer will be greater than that recorded by the other
(4) none of the above

Ria Sarkar asked a question

Subject: Physics, asked on on 20/1/13

why do we need to modulate the frequency?

sumitkanwar148... asked a question

Subject: Physics, asked on on 23/12/11

what are the limitations of amplitude modulation?

Nikita D asked a question

Subject: Physics, asked on on 22/6/14

The block diagram of AM transmitter and AM receiver

Renju & 1 other asked a question

Subject: Physics, asked on on 11/11/12

explain detection of amplitude modulated wave

Akash Sharma asked a question

Subject: Physics, asked on on 3/2/18

Which of the following Boolean expression is not correct :-
(1)

A . B = A + B

(2)

A + B = A . B

(3)

A . B = A . B

(4)

1 + 1 = 1

Nikhil Chaudhari asked a question

Subject: Physics, asked on on 3/3/13

What is meant by detection of modulated carrier wave? Explain briefly steps for detection?

Ajay Singh asked a question

Subject: Physics, asked on on 8/4/19

20 A small ball is released from height Has shown in the figure in avertical circular track, so that it loops inside of the circular track of radius R The value of H must be wing 2R (a) (b) the relation (K and 5R (d) (c) R

Anand Verma asked a question

Subject: Physics, asked on on 26/10/13

what is ground wave propagation

Akash Sharma asked a question

Subject: Physics, asked on on 12/10/17

Q.34. In the figure shown find out the distance Of centre of mass of a system of a uniform circular plate of
radius 3 R from O in which a hole of radius R is cut whose centre is at 2R distance from centre of large circular plate.

(1) R/4
(2) R/5
(3) R/2
(4) none of these

Jignesh Agarkar asked a question

Subject: Physics, asked on on 2/3/13

Which mode of propagation is used by short wave broadcast services having frequency range from a few MHz upto 30MHz? Expain diagrammatically how long distance communication can be achieved by this mode.Why is there an upper limit to frequency of waves used in this mode?

Sir plz..give the answer fast!!!!

Sky asked a question

Subject: Physics, asked on on 18/1/18

Solve this:
Q.2. The temperature of a substance increases by 27

° C

. On the kelvin scale this increase is equal to
(1) 300 K
(2) 2.46 K
(3) 27 K
(4) 7 K

asonianj2011... asked a question

Subject: Physics, asked on on 20/1/12

Why do we use manganine wire in potentiometer?

Shaik Saaduddin asked a question

Subject: Physics, asked on on 24/6/17

The moment of inertia of a body rotating about a given axis is 12.0 kgm² in the SI system. what is the value of the moment of inertia in a system of units in which the unit of length is 5 cm and the unit of mass is 10 g?

Abhee & 1 other asked a question

Subject: Physics, asked on on 4/3/16

write two factors justifying the need of modulating a signal.

Mayank Singh asked a question

Subject: Physics, asked on on 6/1/17

Audio signals cannot be transferred directly into space.Why?
What's the process required to make the transmission of audio signals possible???
Are there any types???

Ck asked a question

Subject: Physics, asked on on 25/10/12

what is square law device?

Jiyarul Haque asked a question

Subject: Physics, asked on on 7/3/18

Q. What are the different compound of TV signal. Write down the bandwidth of speech and TV signal.

V S Jey Govind asked a question

Subject: Physics, asked on on 14/2/12

Sir, Why moon cannot be used as a communication satellite?

Sholong asked a question

Subject: Physics, asked on on 12/2/18

Solve this:
Q.11. What percentage of power of AM wave is carried by the side bands for modulation index m = 1 ?

Jaikhlang Brahma asked a question

Subject: Physics, asked on on 30/10/12

I need to prepare project on Communication System ...can someone help me on it

It is based on the CBSE....and i need it for submission for the partial fullfilment for the requirement for studies in Physics 10+2.

please help me select toic or to prepare.

your help is heartly welcome at: thomasofjnv@gmail.com

before 06 november, 2012.

Jiyarul Haque asked a question

Subject: Physics, asked on on 7/3/18

What are the different transmission medium for communication. Give their bandwidth

Anand Verma asked a question

Subject: Physics, asked on on 26/10/13

What is space wave propagation?

Tanya T asked a question

Subject: Physics, asked on on 23/11/19

What type of modulation is required for television broadcast

Liya Sara Joy asked a question

Subject: Physics, asked on on 16/1/12

explain about downlink and uplink????

Akash Sharma asked a question

Subject: Physics, asked on on 5/10/17

Q 28

8 . A disc rolls down a plane of length L and inclined at angle θ, without slipping . Its velocity on reaching the bottom will be : - (1) \sqrt{\frac{4 gL \sin θ}{3}} (2) \sqrt{\frac{2 gL \sin θ}{3}} (3) \sqrt{\frac{10 gL \sin θ}{7}} (4) \sqrt{4 gL \sin θ}

Supriya Anand asked a question

Subject: Physics, asked on on 2/3/14

A TV tower has a height of 100m. How much population is covered by the TV broadcast if the average population density around the tower is 1000 persons per sq km?

Aswin.k.s asked a question

Subject: Physics, asked on on 25/1/19

When an electromagnetic wave enters an ionized layer of ionosphere the elecctron cloud will oscillate in the electric field of wave with a phase retardation of 90° for a sinusoidal EM. Can u please explain why this happens?

Akshay asked a question

Subject: Physics, asked on on 21/3/12

what is the necessity of modulation?

Aishwarya S asked a question

Subject: Physics, asked on on 2/3/15

what % of am wave power is carried by side bands for m=1

Hasna .p asked a question

Subject: Physics, asked on on 18/3/11

1) What is 'square law device'?What is it's use?
2)What is 'bandpass filter centred'?
3)What is the purpose of 'IF stage'?

Anmol asked a question

Subject: Physics, asked on on 20/12/17

Q10

Q10. An object of mass M starts from rest at the bottom of a fixed incline of height H. A person decides to push the object up the incline in one of two ways with an applied force shown in the diagram. In each of the trials, the object reaches the top of the incline with speed V. How would the work done by the person on the block compare for the two trials ? Assume the same constant non-zero coefficient of kinetic friction between the incline and the object for both trails.

(A) More work would be done in Trial 1

(B) More work would be done in Trial 2

(C) It is impossible to determine for which trial there would be more work done without knowing the value of the speed V.

(D) It is impossible to determine for which trial there would the more work done without knowing the value of the coefficient of kinetic friction.

Meer Abdus Samad asked a question

Subject: Physics, asked on on 4/3/16

how are sidebands produced ?

Naduva asked a question

Subject: Physics, asked on on 3/3/15

Calculate the length of a half wave dipole antenna at 50 MHz. plz answer quickly its urgent

tonyneeranakunnel... asked a question

Subject: Physics, asked on on 19/1/11

why is an FM signal less susceptible to noise than AM signal ?

Akash Sharma asked a question

Subject: Physics, asked on on 26/9/17

Explain Q 6
Q.6. On account of the rotation of earth about its axis :-
(A) the linear velocity of objects at equator is greater than that at other places
(B) the angular velocity of objects at equator is more than that of objects at poles
(C) the linear velocity of objects at all places on the earth is equal, but angular velocity is different
(D) the angular velocity and linear velocity are uniform at all places

Shiva Pillai asked a question

Subject: Physics, asked on on 2/3/16

Derive an expression for covering range of TV transmission tower

Deep Joshi asked a question

Subject: Physics, asked on on 12/7/18

What is the longest wavelength of audio signals to be transmitted in communication system? Give any two reasons.what is done to transmit them to long distances.

Arun Mohan A M & 3 others asked a question

Subject: Physics, asked on on 31/10/14

What is amplitude modulation?

Yash Badgujar asked a question

Subject: Physics, asked on on 21/1/18

Q. Explain, why high frequency carrier waves are needed for effective transmission of Signals.
Q. A message signal of 12 kHz and peak voltage 20 V is used to modulate a carrier wave of frequency 2 MHz and peak voltage 30 V. Calculate the (i) modulation index and (ii) side-band frequencies,

anjalip19... asked a question

Subject: Physics, asked on on 18/1/13

an audio signal is not transmitted directly by converting it into an electromagnetic wave of same frequency.give 2 reasons.

Soumya N asked a question

Subject: Physics, asked on on 14/4/18

Q. A satellite revolves round the earth in a closed elliptical path. If the ratio maximum distance from the earth to the minimum distance is 3 : 2, then the ratio of maximum to minimum speed of the satellite is (1) 3:2 (2) 2:3 (3) 9:4 (4) 4:9

Dadhichi asked a question

Subject: Physics, asked on on 5/3/13

KINDLY PROVIDE THE SOLUTION OF PHYSICS CLASS 12 SET 55/3 OF BOARD 2013 SOON?

Anmol asked a question

Subject: Physics, asked on on 20/12/17

Q13

Q13. A solid sphere of mass m and radius R is rolling without slipping on a rough horizontal surface with angular acceleration

α

. Centre of mass of sphere lies at a distance

\frac{R}{\sqrt{2}}

from the centre of sphere. Find the normal force applied by sphere on the surface at an instant when line joining centre of mass of sphere and centre of sphere makes an angle 45° with vertical and angular velocity of sphere at this instant is

ω

.

(A) mg + \frac{mR}{2} (α - ω^{2}) (B) mg - \frac{mR}{2} (α + ω^{2}) (C) mg + \frac{mR}{2} (α - ω^{2}) (D) mg + \frac{mR}{2} (α + ω^{2})

Tuhinaa Nanda asked a question

Subject: Physics, asked on on 14/11/12

pls explain modulation and demodulation???/

Akash Sharma asked a question

Subject: Physics, asked on on 6/10/17

Q.59. A dancer during rotation folds her hand, due to which her moment of inertia decreases by 50 % then her final angular velocity will becomes -
(1) double
(2) four times
(3) half
(4) remains same

Sneha Pai asked a question

Subject: Physics, asked on on 9/12/13

draw a plot of variation of ' amplitude ' versus 'w ' for an amplitude modulated wave. hence explain the need for keeping the broadcast frequencies sufficiently spaced out ?

Isha asked a question

Subject: Physics, asked on on 13/12/19

Space communication involves sending signal emitted from the antenna of the transmitter to the antenna of the receiver. Describe in brief, mentioning frequency range of operation, four different ways by which space communication becomes possible?

Shivani Sharma asked a question

Subject: Physics, asked on on 24/2/12

X and Y are two parallel plate capacitor having same area of plate and same separation b/w the plates X has air b/w the plates andY has dielectric of dielectric constant k=4

Akash Sharma asked a question

Subject: Physics, asked on on 6/10/17

Q.3. The moment of inertia of a square lamina about the perpendicular axis through its centre of mass is 20 kg-

m^{2}

. Then, its moment of inertia about an axis touching its side and in the plane of the lamina will be :
(1) 10 kg-

m^{2}

(2) 30 kg-

m^{2}

(3) 40 kg-

m^{2}

(4) 25 kg-

m^{2}

Sanjay & 1 other asked a question

Subject: Physics, asked on on 20/6/15

what is html?explain in detail?

Principle Sainik School Satar... asked a question

Subject: Physics, asked on on 21/2/17

Draw the block diagram of an AM receiver and AM transmitter?

Nazmin Hussain asked a question

Subject: Physics, asked on on 20/2/18

Q. 1.In the process of transmission of message/ information signal. noise gets added to the signal anywhere between the information source and the receiving end. Can you think of some sources of noise?

Q. 2.In the process of modulation, new frequencies called sidebands are generated on either side (higher and lower than the carrier frequency) of the carrier by an amount equal to the highest modulating frequency. Is it possible to retrieve the message by transmitting (a) only the side bands. (b) one side band?

Q. 3. In amplitude modulation, modulation index

μ \leq 1

is used. What will happen if

μ > 1

?

Ayush asked a question

Subject: Physics, asked on on 19/2/19

What is line of sight in communication

Prithvi Raj asked a question

Subject: Physics, asked on on 9/12/14

define frequency modulation ? write the advantages of frequency modulation over amplitude modulation ?

Ismail K asked a question

Subject: Physics, asked on on 2/2/14

A message signal of frequency 10kHz and peak voltage 10 V is used to modulate a carrier of frequency 1 MHz and peak voltage of 20V.Determine

a) Modulation Index

b) the side bands produced

Ayman asked a question

Subject: Physics, asked on on 7/11/15

With a block diagram explain elements of communication system.

Joy Shekhar asked a question

Subject: Physics, asked on on 10/1/15

What should be the length of dipole antenna for a carrier wave of frequency 6 X 10⁸ Hz?

Sanjita Prajapati asked a question

Subject: Physics, asked on on 2/1/12

what does line of sight communication means???

Akash Sharma asked a question

Subject: Physics, asked on on 18/3/18

Q A Ball moving with a velocity of 6 m/s strikes an identical stationary ball. After collision each ball moves at an angle of 30

°

with the original line of motion . What are the speeds of the balls after the collision-

1 . \frac{\sqrt{3}}{2} m / s 2 . 3 m / s 3 . 2 \sqrt{3} m / s 4 . \sqrt{3} m / s

Saloni Gupta asked a question

Subject: Physics, asked on on 16/2/13

Why do long distance radio broadcasts use shortwave bands?

Anu Mn asked a question

Subject: Physics, asked on on 4/12/17

What is the different between AM broadcast and FM broadcast ? Give egs

Chowdhury Md. Masood asked a question

Subject: Physics, asked on on 14/6/14

What is the principle behind the working of stethoscope? Kindly answer sir/mam.

Anand Verma asked a question

Subject: Physics, asked on on 26/10/13

What is sky wave propagation ?

Aditi Singh asked a question

Subject: Physics, asked on on 22/11/14

what is modulation ?explain the amplitude modulation with the help of necessary diagram.what is meant by modulation index and the lower and upper side bands?

Ravi Kant asked a question

Subject: Physics, asked on on 10/4/13

A diode detector is used to detect an amplitude modulated wave of 60% modulation by using a condenser of capacity 250 pico farad in parallel with a load resistance 100 kilo ohm. Find the maximum modulated frequency which could be detected by it

Mathai Kocuplamveedu asked a question

Subject: Physics, asked on on 25/2/15

Draw a block diagram showing the important components of a communication system. What is the function of a transducer?

deepakajithdbz... asked a question

Subject: Physics, asked on on 9/11/10

Difference between transducer and transmitter?

Akash Sharma asked a question

Subject: Physics, asked on on 5/10/17

Q.49. Calculate the ratio of the times taken by a uniform solid sphere and a disc of the same mass and the same diameter to roll down through the same distance from rest on a smooth inclined plane.
(1) 15 : 14
(2)