31- What is the unit of surface tension?
(A) N/m
(B) N/m2
(C) Nm-1
(D) Nm-3
32- In Fraunhofer diffraction, the wave front is
(A) Spherical wave front
(B) Plane wave front
(C) Cylindrical wave front
(D) Elliptical wave front
33- The elastic limit depends upon
(A) density of the wire
(B) temperature of the wire
(C) radius of the wire
(D) pressure of the wire
34- The chromium ions doped in the ruby rod
(A) absorbs red light
(B) absorbs green light
(C) absorbs blue light
(D) emits green light
35- The length determined by an observer at rest with respect to the object is
(A) length contraction
(B) proper length
(C) relative length
(D) reference length
36- The wavelength of He-Ne laser is
(A) 6328 Å
(B) 6828 Å
(C) 6943 Å
(D) 5500 Å
37- A cylindrical bottle resting on its side is in ___ equilibrium.
(A) neutral
(B) natural
(C) unstable
(D) stable
38- The surface of the soap bubble colored in sunlight due to
(A) polarization
(B) diffraction
(C) interference
(D) deviation of light
39- A body in motion can be located with reference to some coordinate system called
(A) the frame of reference
(B) cycloid
(C) non-inertial frame
(D) inertial frames of reference
40- The sensor used for automatic operation of street light is
(A) Stress sensor
(B) Voltage sensor
(C) Photo electric sensor
(D) Dielectric sensor
ANSWERS:
31-(C), 32-(B), 33-(C), 34-(B), 35-(B), 36-(A), 37-(A), 38-(C), 39-(A), 40-(C)