Q.1.
A slab consists of two layers of different materials of the same thickness and having thermal conductivities. x and y are connected in series. The equivalent thermal conductivity of the slab is
-
5%
x+y
-
25%
$\sqrt {xy}$
-
40%
$\frac {xy}{x+y}$
-
30%
$\frac {2xy}{x+y}$
Q.2.
A metal rod at a temperature of 150° C radiates energy at a rate of 20 W. if its temperature is increased to 300° C, then it will radiate at the rate of
-
25%
17.5 W
-
10%
37.2 W
-
45%
40.6 W
-
20%
68.3 W
Q.3.
The Wien’s displacement law express the relation between
-
60%
wavelength corresponding to maximum energy and temperature
-
7%
radiation energy and wavelength
-
33%
temperature and wavelength
-
0%
colour of light and temperature
Q.4.
The latent heat of vaporisation of a substance is always
-
61%
greater than its latent heat of fusion
-
17%
greater than its latent heat of sublimation
-
17%
equal to its latent heat of sublimation
-
6%
less than its latent heat of fusion
Q.5.
A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is
-
21%
E/c
-
57%
2E/c
-
0%
Ec
-
21%
E/c2
Q.6.
Steam at 100° C is passed into 1.1 kg of water contained in calorimeter of water equivalent 0.02 kg at 15 ° C till the temperature of the calorimeter rises to 80 ° C. What is the mass of steam condensed?
Latent heat of stem =536 cal/g
-
11%
.065
-
44%
.195
-
44%
.130
-
0%
.260
Q.7.
An ideal black body at room temperature is thrown into a furnace. It is observed that
-
58%
Initially, it is the darkest body and at later times the brightest.
-
25%
It is the darkest body at all times.
-
8%
it cannot be distinguished at all times.
-
8%
Initially, it is darkest and at later times it cannot be distinguished.
Q.8.
Which of the following processes is reversible?
-
36%
Transfer of heat by conduction
-
18%
Transfer of heat by radiation
-
18%
Isothermal compression
-
27%
Electrical heating of a nichrome wire
Q.9.
A bimetallic strip consists of metals X and Y. It is mounted rigidly at the base as shown. The Metal X has a higher coefficient of expansion compared to that for metal Y. When the bimetallic strip is placed in a cold bath
-
45%
it will bend towards the right
-
55%
it will bend towards the left
-
0%
it will not bend but shrink
-
0%
it will neither bend nor shrink.
Q.10.
Two identical rods are connected between two containers one of them is at 100 ° C and another is at 0 °C. If rods are connected in parallel then the rate of melting of ice is a j/s. If they are connected in series then the rate is b. The ratio a/b is
-
12%
2 :1
-
25%
1: 2
-
38%
4: 1
-
25%
1: 4
Q.11.
In the following question, a statement of assertion is followed by a statement of reason. You are required to choose the correct one out of the given four responses and mark it as
(a) If both assertion and reason are true and reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not correct explanation of the assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.
(e) If reason is true but assertion is false.
Assertion: In a pressure cooker the water is brought to a boil. The cooker is then removed from the stove. Now on removing the lid of the pressure cooker, the water starts boiling against.
Reason: The impurities in water bring down its boiling point
-
40%
a
-
20%
b
-
20%
c
-
20%
d
-
0%
e
Q.12.
In the following questions, a statement of assertion is followed by a statement of reason. You are required to choose the correct one out of the given four responses and mark it as
(a) If both assertion and reason are true and reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not correct explanation of the assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.
(e) If reason is true but assertion is false.
Assertion: For higher temperatures the peak emission wavelength of a black body shifts to lower wavelengths.
Reason: Peak emission wavelengths of a blackbody is proportional to the fourth power of temperature.
-
17%
a
-
33%
b
-
17%
c
-
33%
d
Q.13.
In the following questions, a statement of assertion is followed by a statement of reason. You are required to choose the correct one out of the given four responses and mark it as
(a) If both assertion and reason are true and reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not correct explanation of the assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.
(e) If reason is true but assertion is false
Assertion: Woolen clothes keep the body warm in winter
Reason: Air is bad conductor of heat
-
20%
a
-
0%
b
-
60%
c
-
0%
d
-
20%
e
Q.14.
In the following questions, a statement of assertion is followed by a statement of reason. You are required to choose the correct one out of the given four responses and mark it as
(a) If both assertion and reason are true and reason is the correct explanation of the assertion.
(b) If both assertion and reason are true but reason is not correct explanation of the assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.
(e) If reason is true but assertion is false.
Assertion: it is hotter over the top of fire than at the same distance on the sides.
Reason: Air surrounding the fire conducts more heat upwards.
-
57%
a
-
14%
b
-
29%
c
-
0%
d
-
0%
e
Q.15.
Match the physical quantities given in List I to their dimensions in List II.
-
36%
P -> 4,Q -> 2,R ->1,S -> 3
-
36%
P -> 3,Q -> 2,R ->1,S -> 4
-
27%
P -> 4,Q -> 1,R ->2,S -> 3
-
0%
P -> 2,Q -> 3,R ->1,S -> 4
Q.16.
Column I gives some devices and Column II gives some processes on which the functioning of these devices depend. Match the devices in Column I with the processes in Column II.
-
40%
A->p, B -> q, C -> s, D -> r
-
10%
A->s, B -> p, C -> q, D -> r
-
30%
A->r, B -> q ,C -> p, D -> s
-
20%
A->s, B -> q, C -> p, D -> r
Q.17.
The pressure of the gas in constant volume gas thermometer are 80 cm,90cm and 100cm of mercury at the ice point, the steam point and in a heated wax bath resp. Find the temperature of the wax bath
-
33%
150
-
33%
200
-
17%
180
-
17%
100
Q.18.
At a common temperature, a block of wood and a block of metal feel equally cool or hot. The temperatures of metal and wood are
-
0%
less than the temperature of the body
-
29%
equal to the temperature of the body
-
14%
greater than the temperature of the body
-
57%
either (a) or (c)
Q.19.
A sphere, a cube, and a disc all of the same material, quality, and volume are heated to 600 ºC and left in the air. Which of these will have the lowest rate of cooling?
-
29%
Sphere
-
14%
Cube
-
0%
Disc
-
57%
All will have the same rate
Q.20.
Mud houses are cooler in summer and warmer in winter because
-
43%
mud is a bad conductor of heat
-
29%
mud is a superconductor of heat
-
29%
mud is a good conductor of heat
-
0%
none of the above