1. Light
a) Is a form of Heat energyb) Is a form of Electrical energy
c) Consists of electro-magnetic waves
d) Consists of
2. Visible spectrum of the light has a wavelength in the range of:
a) 1000 to 4000 Aob) 4000 to 7000 Ao
c) 7500 to 12500 Ao
d) 12500 to 30000 Ao
3. Luminous flux is:
a) The rate of energy radiation in the form of light wavesb) The part of light energy radiated from light source
c) Measured in Lux
d) Both a and c
4. Candela is the unit of:
a) Illuminationb) Luminous intensity
c) Luminance
d) Light energy
5. Sky appears to be blue because of:
a) Radiation of light over dust particlesb) Reflection of light over dust particles
c) Refraction of light over dust particles
d) Scattering of light over dust particles
6. Candle power is:
a) The luminous flux emitted by the source per unit solid angleb) The part of the light energy radiated by the sun that is received by earth
c) Measured in Lux
d) None of the above
7. An object which appears to be red to the eyes absorbs:
a) Blue radiationb) Violet radiation
c) Green radiation
d) Absorbs all the above radiation
8. Which of the following colour has the wavelength between blue and yellow:
a) Violetb) Orange
c) Red
d) Green
9. Which of the materials is most commonly used for the filaments in the incandescent lamps:
a) Tungstenb) Tin
c) Silver
d) Asbestos
10. The expected life of an incandescent lamp is about:
a) 100 hoursb) 200 hours
c) 500 hours
d) 1000 hours
