1) When water solidifiers to ice
a) heat is absorbed
*b) heat is released
c) temperature increases
d) temperature decreases
2) The wavelength range of infrared rays is
a) 107m to 7.8 x 103 m
b) 10-7m to 7.8 x 10-3m
*c) 10-3m to 7.8 x 10-7 m
d) 103m to 7.8 x 107 m
3) Raindrops assume spherical shape due to
a) gravitational force
*b) surface tension
c) centrifugal force
d) centripetal force
4) The frequency range of ultrasound is
a) below 20 kHz
b) below 2 kHz
*c) above 20 kHz
d) above 20,000 kHz
5) When travelling at the speed of light ,one can reach the moon in
a) 5 seconds
*b) 2 seconds
c) 5 minutes
d) one minute
6) when the velocity of a particles travelling with a velocity nearly equal to the velocity of light, increases,its mass
a) increases
b) decreases
*c) remains the same
d) none of these
7) The type of ray that appears to originate outside the earth is
a) x-rays
b) cosmic rays
c) alpha rays
*d) beta ray
8) in fluorescent tubelight
a) visible light is converted into visible light
b) visible light is converted into ultraviolet light
c) ultraviolet light is converted into ultraviolet light
*d) ultraviolet light is converted into visible light
9) The radius of curvature of concave mirror is 20cm. its focal length is
a) 5cm
*b) 10cm
c)20cm
d) 40cm
10) The electrical energy consumed by a 3 kW stove which is switched on for 6 hours is
a) 2 units
*b) 18 units
c) 0.5 units
d) 500 units
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