Purpose of an optical filter is to

• reflect lights of different colours

• dispense light into component colours

• refract light of different colours

• refract light of different colours

If electric resistance is to be decreased, then the number of resistances should be connected in

• Series

• Parallel

• Mixed arrangement

• Mixed arrangement

The 'Choke' used with a tube light is basically .............

• an inductor

• a capacitor

• a transformer

• a transformer

A good conductor while carrying current is

• negatively charged

• positively charged

• electrically neutral

• alternately charged positive and negative

Which phenomenon is responsible for the echo of sound wave?

• Reflection

• Refraction

• Interference

• Interference

The washing machine works on the principle of

• Dialysis

• Diffusion

• Reverse osmosis

• Reverse osmosis

Temperature of distant luminous bodies can be determined by

• Mercury thermometers

• Gas thermometers

• Pyrometers

• Pyrometers

Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules is

• Conduction

• Convection

• Radiation

• Radiation

Curie is a unit of .............

• radioactivity

• energy of Gamma rays

• intensity of Gamma rays

• intensity of Gamma rays

What type of force acts on a car moving around a curve?

• Centrifugal force

• Cohesive force

• Centripetal force

• Centripetal force