# National Standard Examination in Physics (NSEP) Solved Paper 2016 Part-9

Q: 30. A vibrator of frequency f is placed near one end of a long cylindrical tube. The tube is fitted with a movable piston at the other end. An observer listens to the sound through a side opening. As the piston is moved through 8.75 cm, the intensity of sound recorded by the observer changes from a maximum to a minimum. If the speed of sound in air is 350 m/s, the frequency f is

(A) 500 Hz

(B) 1000 Hz

(C) 2000 Hz

(D) 4000 Hz

Q: 31. A heavy metal block is dragged along a rough horizontal surface at a constant speed of 20 km/hr. The coefficient of friction between the block and the surface is 0.6. The block is made of a material whose specific heat is 0.1 cal/g-°C and absorbs 25% of hear generated due friction. If the block is dragged for 10 min, the rise in temperature of the block is about

(A)

(B)

(C)

(D) Data insufficient

Q: 32. A gas is made to undergo a change of state from an initial state to a final state along different paths by adiabatic process only. Therefore.

(A) The work done is different for different paths

(B) The work done is the same for all paths

(C) There is no work done as there is no transfer of energy

(D) The total internal energy of the system will not change

Q: 33. The breakdown field for air is about Therefore, the maximum charge that can be placed on a sphere of diameter 10 cm is

(A)

(B)

(C)

(D)

Q: 34. A wire in the shape of a square frame carries a current I and produces a magnetic field at its centre. Now the wire is bent in the shape of a circle and carries the same current. If is the magnetic field produced at the centre of the circular coil, then

(A)

(B)

(C)

(D)