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Aparna Sahu
Subject: Physics
, asked on 31/1/18
Q. 512 calories of radiation is incident on a body. It absorbs 220 calories the coefficient of emission is
(a) 0.43
(b) 0.57
(c) 1.7
(d) 0.34
Answer
2
Aparna Sahu
Subject: Physics
, asked on 31/1/18
Solve this.
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.
50
°
C
/
m
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50
°
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30
°
C
a
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?
24
°
C
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18
°
C
/
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30
°
C
/
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12
°
C
/
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Answer
1
Aparna Sahu
Subject: Physics
, asked on 31/1/18
Solve this.
Q). Two stars A and B radiate maximum energy at 3600
°
A and 3600
°
A respectively. Then the ratio of absolute temperatures of A and B is
1. 257 : 21
2. 85 : 16
3. 3 : 4
4. 4 : 3
Answer
1
Aparna Sahu
Subject: Physics
, asked on 30/1/18
Solve this.
Q. A cup of tea cools from 80
°
C to 60
°
C in one minute. The ambient temperature is 30
°
C. in cooling from 60
°
C to 50
°
C, it will take.q
A. 50 sec
B. 90 sec
C. 60 sec
D. 30 sec
Answer
1
Aparna Sahu
Subject: Physics
, asked on 30/1/18
Solve this.
Q. The coefficient of transmission and coefficient of reflection for a given body at a given temperature are 0.33 and 0.64 respectively. Then the coefficient of emission of the same body at the same temperature will be
A. 0.3
B. 0.003
C. 0.03
D. 0.33
Answer
1
Aparna Sahu
Subject: Physics
, asked on 30/1/18
Solve this.
Q. If a = 0.72, r = 0.24, then the value of t is
A. 0.02
B. 0.04
C. 0.4
D. 0.2
Answer
1
Aparna Sahu
Subject: Physics
, asked on 29/1/18
Q
.
300
g
o
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r
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q
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s
30000
J
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25
°
C
t
o
85
°
C
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A
100
J
K
-
1
B
200
J
K
-
1
C
400
J
K
-
1
D
500
J
K
-
1
Answer
1
Aparna Sahu
Subject: Physics
, asked on 29/1/18
Solve this.
Q). Provided that latent heat of fusion of a 5.4 kg block of ice has been provided by a heater of 1 kW for 1800 s, specific latent heat of fusion of ice would then be equal to
A. 333 kJ / kg
B. 340 kJ / kg
C. 350 kJ / kg
D. 360 kJ / kg
Answer
1
Aparna Sahu
Subject: Physics
, asked on 28/1/18
Solve this.
Q. A thin aluminium plate has a surface area of 1,500
m
2
at 20
°
C. What will be its surface area when it is cooled to - 20
°
C?
(Take the linear expansivity of aluminium to be
2
.
5
×
10
-
5
K
-
1
)
Answer
1
Aparna Sahu
Subject: Physics
, asked on 24/1/18
Solve this :
A machine is used to lift a load of 20 N through a height of 10 m. If the efficiency of the machine is 40% how much work is done ?
Answer
1
Aparna Sahu
Subject: Physics
, asked on 23/1/18
A
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tan
k
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s
(
1
)
8
.
29
k
N
(
2
)
2
.
89
k
N
(
3
)
9
.
28
k
N
(
4
)
28
.
9
k
N
Answer
3
Dhinesh Vijayan
Subject: Physics
, asked on 22/1/18
Pls solve this
Q). A conducting bar of mass m and length
l
is given an initial velocity
v
0
on a smooth horizontal conducting rail containing an inductance L. If the applied magnetic field has inward field induction
B
→
, find the maximum distance covered by the bar before it stops.
Answer
3
Dhinesh Vijayan
Subject: Physics
, asked on 21/1/18
In the figure shown switch S
1
, remains connected for a long time and the switch S
2
remain open. Now the switch S
2
is closed. Assuming ε = 10 V and L = 1 H. Find the magnitude of rate of change of current in inductor (A/s) just after the switch S
2
is closed.
Answer
1
Yatharth
Subject: Physics
, asked on 20/1/18
Plz tell how area has increased of loop as area remains constant.{The reason given in ans}.
Q. (a) A wire of irregular shape turning into a circular shape.
(b) A circular loop being deformed into a narrow straight wire.
Ans (a) As the loop changes from irregular to circular shape, its area increases. Hence the magnetic flux linked with it increases. According to Lenz's law, the induced
Answer
1
Aparna Sahu
Subject: Physics
, asked on 19/1/18
Q. The r.m.s velocity of oxygen molecules at 27
°
C is 318 m/s. the r.m.s velocity of hydrogen molecules at 127
°
C is
1470 m/s
1603 m/s
1869 m/s
2240 m/s
Answer
1
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Next
What are you looking for?
(a) 0.43
(b) 0.57
(c) 1.7
(d) 0.34
Q). Two stars A and B radiate maximum energy at 3600 A and 3600 A respectively. Then the ratio of absolute temperatures of A and B is
1. 257 : 21
2. 85 : 16
3. 3 : 4
4. 4 : 3
Q. A cup of tea cools from 80C to 60C in one minute. The ambient temperature is 30C. in cooling from 60C to 50C, it will take.q
A. 50 sec
B. 90 sec
C. 60 sec
D. 30 sec
Q. The coefficient of transmission and coefficient of reflection for a given body at a given temperature are 0.33 and 0.64 respectively. Then the coefficient of emission of the same body at the same temperature will be
A. 0.3
B. 0.003
C. 0.03
D. 0.33
Q. If a = 0.72, r = 0.24, then the value of t is
A. 0.02
B. 0.04
C. 0.4
D. 0.2
Q). Provided that latent heat of fusion of a 5.4 kg block of ice has been provided by a heater of 1 kW for 1800 s, specific latent heat of fusion of ice would then be equal to
A. 333 kJ / kg
B. 340 kJ / kg
C. 350 kJ / kg
D. 360 kJ / kg
Q. A thin aluminium plate has a surface area of 1,500 at 20 C. What will be its surface area when it is cooled to - 20 C?
(Take the linear expansivity of aluminium to be )
A machine is used to lift a load of 20 N through a height of 10 m. If the efficiency of the machine is 40% how much work is done ?
Q). A conducting bar of mass m and length is given an initial velocity on a smooth horizontal conducting rail containing an inductance L. If the applied magnetic field has inward field induction , find the maximum distance covered by the bar before it stops.
Q. (a) A wire of irregular shape turning into a circular shape.
(b) A circular loop being deformed into a narrow straight wire.
Ans (a) As the loop changes from irregular to circular shape, its area increases. Hence the magnetic flux linked with it increases. According to Lenz's law, the induced