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Syllabus

State the principal and working of a meter bridge?

(1) 10 V

(2) 8 V

(3) 6 V

(4) Zero

On what factors the internal resistence of a cell depends ?

Draw an equipotential surface due to an electric dipole.

why are alloys manganin constantan used to make standard resistance coil?

project onto study various factors on which the internal resistance/emf of a cell depends.

current density and number of free electrons per unit volume

answer-

current density=2.4*1)^5A/m square

n=8.8*10^28

Define 1 Ampere.

why is it safe to sit inside a car during a thunderstorm ?

derivation for ampere circuital law?

C. The effective resistance between A and B will be(1) $\frac{1}{3C}$ (2) $\frac{1}{2C}$ (3) $\frac{1}{C}$ (4) $\frac{1}{4C}$

How to solve an unbalanced Wheatstone bridge?

how can sensitivity of potentiometer be increased

A 3 m long copper wire carrying a current of 3 A.. How long does it take for an electron to drift from one end to other end ? The cross- sectional area of the wire is 2 * 10 ^ -6 m

^{2}and the number of conduction electrons in copper is 8.5 * 10 ^ 28 m^{-3}.What is the dimensional formula of potential difference

Example 138. using Kirchhoff's laws in the electrical network shown in Fig. 3.148, calculate the values of ${I}_{1},{I}_{2}and{I}_{3}$.

What is the definition of meter bridge?

What are the conditions for total internal reflection?

a 10 C charge flows through a wire in 5 minutes the radius of the wire in 1 mm it contains 5 x 10^22 electrons per centimetre cube calculate the current and drift velocity....

the emf of a cell is always greater than its terminal voltage.why?give reason.

why is potentiometer preferred over voltmeter?

what is the dimension of resistance....????

Thank you

a copper wire is streched to make it 0.1%lonnger.what is the percentage change in resistance?

A 80uF capacitor is charged by a 50V battery.The capacitor is disconnected from the battery and then connected across another uncharged 320 uF capacitor. Calcuulate the charge on the second capacitor.

what is vacus junction?

53. Figure shows a circuit with known resistance R

_{1}& R_{2}. Neglect the internal resistance of the sources of the current and resistance of the connecting wire. The magnitude of electromotive force E_{1}such that the current through the resistance R is zero will be.$a)E{R}_{1}/{R}_{2}B)E{R}_{2}/{R}_{1}C)\frac{E({R}_{1}+{R}_{2})}{{R}_{2}}D)\frac{E{R}_{1}}{\left({R}_{1}+{R}_{2}\right)}$

A balloon starts rising from ground rest with an upward acceleration 2 m/secsqu. just after 1 sec. a stone is dropped from it the time taken by stone to strike the ground is nearly?

(a) 40 cm

(b) 20 cm

(c) 300/7 cm

(d) 240/7 cm

the resistance of the platinum wire of a platinum resistance thermometer at the ice point is 5 ohm and at steam point is 5.23 ohm .When the thermometer is inserted in a hot bath , the resistance of the platinum wire is 5.795 ohmcalculate the temprature of the bath

Q.73. In the following circuit if ${V}_{A}-{V}_{B}$ = 4 V, then the value of resistance X in ohms will be :-

(1) 5

(2) 10

(3) 15

(4) 20

what are the advantages of potentiometer over votlmeter ?

show that electric field is conservative?

the reading on a high resistance voltmeter when a cell is connected across it is 2.2 v . When the terminal of the cells are also connected to a resistance of 5 v ,the voltmeter reading drops to 6.8 v . Find the internal resistance of the cell?????(i)What is the purpose of using high resistance R2?

(ii) How does the position of balance point (J) change when the resistance R1 is decreased?

(iii) Why cannot the balance point be obtained

(1) when the emf E is greater than 2V and

(2) when key (K) is closed?

1)60 W bulb will fuse. 2)100 W bulb will fuse 3)both bulbs will fuse.

4)Bulbs will not fuse

_{d}and the resistance R affected when(i)V is doubled

(ii)I is doubled and

(iii)D is doubled?

In a galvanometer there is deflection of 10 divisions per mA.Thje internal resistance of the galvanometer is 60 ohm.If a shunt of 2.5 ohm is connected to the galvanometer and there are 50 divisions in all,on the scale of galvanometer,what maximum current can this galvanometer read?

MY DOUBT IS:(If wrong plz correct it and explain) Since there are 50 divisions in all in the galvanometer,then maximum current that galvanometer would read is I_{g}=50*1/10=5 mA .But the answer is given 125 mA.How?The cell has an emf of 2 V and the internal resistance of this cell is 0.1 ohm. It is connected to resistance of 3.9 ohm. What will be The voltage across the cell?

how does drift velocity of electron in a metallic conductor vary with temperature?

Q. For the circuit shown calculate the potential difference between point B and D.

Using Kirchhoff’s Law determine the current I1, I2 and I3 for the network shown below:

A steady current flows in a metallic conductor of non-uniform cross section.Which of these quantities is constant along the conductor-

1)Current

2)Current density

3)Drift speed

4)Electric field

the resistance of a silver wire at 0 degree celsius is 1.25 ohm.upto wat temp. it must b heated so dat its resistance is doubled?(alpha silver=0.00375/degree celsius.will d temp. be same for all silver conductors of all shapes??

A resistance or R ohm draws a current from a potentiometer.The potentiometer has a total resistance R

_{0}ohm.A voltage V is supplied to the potentiometer .Derive an expression for the voltage fed to the ckt when the slide is in the middle of the potentiometer.A wire of resistance 8R is bent in the form of a circle. What is the effective resistance between the ends of a diameter AB?

Six cells, each of emf 5V and internal resistance 0.1 ohm are connected as shown in Figure. The reading of the ideal voltmeter V is:

Explain the variation of conductivity nwith temp for (a) A metallic conductor (b) ionic conductor

WHAT IS MEANT BY DIELECTRIC POLARIZATION.???

HOW CAN WE ESTABLISH THE RELATION K = 1+x

Two conducting wires X and Y of same diameter but different material are joined in series across the battery. If the number density of electron in X is twice that in Y, fined ratio of drift velocity of electron in two wires

6.If potential of A is 10V, then potential of B is -(A) 25/3 V (B) 50/3 V (C) 100/3 V (D) 50 V

a uniform wire of resistance 36 ohm is bent in tne form of a circle .calculate the effective resistance across the points A and B.

why do we perfer a 10 wire potentiometer to 4 wire potentiometer ?

is current is scalar or vector quantity?

two cells of emf 6v and 12v and internal resistance 1ohm and 2ohm respectively are connected in parallel so as to send a current in the same direction through an ext . resistence of 15ohm.using kirchhoff's law calculate curent through each branch of the circuit and p.d. across 15onm resistor

The supply voltage to a room is 120V.The resistance of lead wires is 6 ohm.A 60 W bulb is already switched on.What is the decrease of voltage across the bulb when a 240 W heater is switched on in parallel with the bulb?

a)0 V b)2.9 V c)13.3 V d) 10.04 V

(i) When the key k is open, how does the balance point change if current from the driver cell de-creases?

(ii) When the key k is closed, how does the balance point change if R is increased keeping current from the driver cell constant?

Drift Speed of Electrons is of the order of 10

^{-3}ms^{-1}, but current is established in the circuit with the speed of Light. ExplainMy Question:

Draw V-I Graph for both ohmic and non-ohmic materials stating one example of each as well.thanks!

ans is 6*10^-4, 3.75*10^15

a wire of 15 ohm resistance is gradually stretched to double its original length. it is then cut into two equal parts. these parts are connected in parallel across a 3 V cell. find the current drawn from the cell

A storage battery of emf 8V and internal resistance 0.5 ohm is being charged by a 120 V d.c supply using a series resistor of 15.5 ohm. What is the terminal voltage of the battery during charging? what is the purpose of having a series resistor in the charging ciruit?

When two wires are in the gaps of the meter bridge, the balance point was foun d to be 1/3m from the zero end. When a 6ohm coil is connected in series with the smaller of the the two ressistance, the balancing point is shifted to 2/3m from the same end. Find the resistance of the wires?

12 identical resistance R each form a cube . Resistance across its face diagonal corners is?

Draw the circuit diagram and using Kirchhorf's laws, calculate the current through each branch of the circuit and potential difference across the 5 ohm resistor.

Ans 200 ohm,5*10^-3 A.

Dont give link.

derive the expression for drift velocity in an electric field.

please answer all of them. they are from meter bridge experiment class 12

2. If the metre bridge wire is not of uniform area of cross section,

how will it affect the observations?

Fig. E 2.3 Defective scale of a metre bridge

3. If the metre bridge wire is not made of a material of uniform density,

how will it affect the observations?

4. If the same experiment is performed with AC = 50 cm wire instead

of 1 m, what changes would be there in the result?

5. The scale attached along the wire may not indicate the exact

length as shown in Fig. E 2.3. How would you minimise the error?

6. Why is the metre bridge not suitable for measuring very

high/very low resistances?

7. Why is the metre bridge preferred for determining the resistanceof a wire over the Ohms law circuit

what are kirchhoff's law?explain them.

An electric kettle was marked 500 watts, 230volts and was found to bring 1kg of water at 15 degree centigrade to boiling point in 15 minutes. Determine the heat efficiejncy of the kettle.

give two possible causes for one sided deflection in a potentiometer experiment.

why is a copper wire used in a sonometer to find the frequency of A.C mains?plz i hv my board practicals 2morow.friends and xperts plz help

how does internal resistance of a cell vary with temperature? pls answer me.

1 NEWTON =how many dyne?

80. There are 32 cells each having emf 1 V and internal resistance 1 $\Omega $. All the cells are connected together in a closed loop. When terminal voltage of cells are measured, they are found to be either 0.5V or 1.5 V. How many cells are having their polarities reserved with respect to the majority of cells?

(1) 6 (2) 12

(3) 8 (4) 10

A cylindrical metallic wire is stretched to increase its length by 5%. Calculate the percentage change in its resistance.

The sequence of coloured bands in two carbon resistors R

_{1}and R_{2}is (1) brown, green , blue and (2) orange, black and green.Find the ratio of the currents flowing through them, when connected in parallel to a 15 V batterywhat is the main difference between DC n AC current???

In example no 3.6 at page 116 of NCERT Physics, the value of R is found to b 5/6 ohm.. bt i think that it's incorrect.. it shud b 5/4 ohm...

Even if v put the valur of R=5/6 ohm in the formula I=V/R then v dnt get the current I as 4 A.. But on putting R=5/4 ohm, v get the correct value of I too. So it shud b 5/4 and not 5/6....

Isnt it.....????????