2019-03-01_Physics_Times

A hollow spherical ball of inner radius a and outer

radius 2a is made of a uniform material of constant

thermal conductivity K. The temperature within the

ball is maintained at

An ideal heat engine has an efficiency

Two identical containers joined by a small pipe

initially contain the same gas at pressure

(a)

0

2 2

Rq

v

x

(b)

0

2

4 Rq

v

x

(c)

0

2

Rq

v

x

(d)

Rq (^0) v
x
2 T 0 and outside the ball is T 0.
Find the temperature at
3
2
a
r
(a)^0
7
5
T
(b)^0
4
3
T
(c)^0
5
3
T
(d)^0
3
2
T
. The
coefficient of performance of the engine when
driven backward will be
(a)
  1
 
 
(b)
1
1
 
 
 
(c)
1
1
 
 
 
(d)
1
1
 
 
 
p 0 and
absolute temperature T 0. One container is now
maintained at the same temperature while the other
is heated to 2 .T 0 The common pressure of the
gases will be
(a)
A gaseous mixture consists of 16g of helium and
16 g of oxygen. The ratio
0
4
3
p (b)^30
2
p (c) 2 p 0 (d) 0
5
3
p
C Cp/ V of the mixture is:
(a) 1.54 (b) 1.4 (c) 1.62 (d) 1.59
The radius of curvature of the particle w.r.to the
trolley is
(a) 8 2m (b) 25 2m
(c) 5 2m (d) 20 2m
The following four wires of length L and radius r
are made of the same material. Which of these will
have the largest extension, when the same tension
is applied?
(a) 100 , 0.2
When a ball is released from rest in a very long
column of viscous liquid, its downward
acceleration is ‘a’ (just after release). Then its
acceleration when it has acquired two third of the
maximum velocity:
(a)
L cm r mm
(b) L 200 cm r, 0.4mm
(c) L 300 cm r, 0.6mm
(d) L^400 cm r, 0.8mm
3
a
(b)
2
3
a
(c)
6
a
(d) None of these
The correct order in which the dimensions of
“length” decreases in the following physical
quantities is
A. Coefficient of viscocity
B. Energy
C. Escape velocity
D. Density
(a) B, C, A, D (b) A, B, C, D
(b) C, D, B, A (d) A, D, C, B
Three identical thin rods, each of mass m and length
6.
7.
8.
9.
10.
11.
12.
13.
14.
, are joined to form an equilateral triangular frame.
The moment of inertia of the frame about the axis
parallel to its one side and passing through the
opposite vertex is
(a)
(^32)
2
m (b)^2
5
4
m (c)^2
5
2
m (d)^2
5
3
m