The circular divisions of shown screw gauge are 50. It moves 0.5 mm on main scale in one rotation. The diameter of the ball is
 
 1) 2.25 mm
 2) 2.20 mm
 3) 1.20 mm
 4) 1.25 mm

A vertical smoked plate falls vertically under gravity and traces found by transverse vibrations of a fork show 10 complete vibrations in each of two consecutive lengths which differ by 1.8cm. The frequency of the fork is

1) 233.3 Hz
2) 333.3 Hz
3) 444.3 Hz
4) 555.3 Hz

 A wire tension 225 N produces 6 beats per second when it tuked with a fork, when the tension changed to 256 N, it again tuned with the same tuning fork to no. of beats remained unchanged, the frequency of tuning fork will be

(1) 186             (2) 280

(3) 225             (4) 256

The magnification of an object placed in front of a convex lens of focal length 20 cm is is +2. To obtain a magnification of -2, The object has to be moved a distance equal to:

1) 10 cm
2) 20 cm
3) 30 cm
4) 40 cm

A concave mirror is placed over a beaker containing water of (µ = 1.33) and image of the object placed at the bottom of beaker is formed at a distance of 25 cm from the top then focal length of the mirror is

 Absorption coefficient of an ideal blackbody is :

(1) less then 1
(2) 1
(3) zero
(4) infinity

The kinetic energy of a particle in S.H.M. is 9J when it passes through the mean position. If its mass is 2 kg and the amplitude is 1m, the time period is:

1) 2.09 s
2) 3.14 s
3) 2.57 s
4) 1.79 s

Two marbles, one twice as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the ground, the heavier marble has:

1. Twice as much kinetic energy as the lighter one.

2. The same kinetic energy as the lighter one.

3. Four times as much kinetic energy as the lighter one.

4. Half as much kinetic energy as the lighter one.

The velocity factor of a transmission line is 0.62. Calculate dielectric constant of the insulation used

1) 2.6

2)  3

3) 4

4) 5

A parallel plate capacitor with air between the plates has capacitance of $$9 pF$$. The separation between its plates is '$$d$$'. The space between the plates is now filled with two dielectrics. One of the dielectrics has dielectric constant $$k_1=3$$ and thickness $$\dfrac {d}{3}$$ while the other one has dielectric constant $$k_2=6$$ and thickness $$\dfrac {2d}{3}$$. Capacitance of the capacitor is now :

1) 1.8 pF

2) 45 pF

3) 40.5 pF

4) 20.25 pF