The document defines luminous intensity as the amount of light emitted by a light source per unit solid angle in a particular direction. The SI unit of luminous intensity is the candela, which is approximately equal to the amount of light emitted by a common wax candle. Luminous intensity is measured using a photometer, which directly provides the intensity in candela.

3. ‘Luminous’ means giving
off light.
‘Intensity’ means brightness.
LUMINOUS INTENSITY

4. Some objects emit light
on their own.
So they are called
luminous objects

5. Can you say some objects that emit light?
SUN STAR
CANDLE ELECTRIC BULB

7. Amount of light emitted by a
light source, in a particular
direction, per unit solid
angle is called luminous
intensity.

8. The SI unit of
luminous intensity
is candela and is
denoted by ‘cd’.

9. Light emitted by a candle
is equal to one candela.
What is one Candela?
One Candela is
approximately equal to
the light emitted by a
common wax candle.

10. Umpires checking the intensity of light

11. Luminous intensity is measured by a Photometer
which gives the luminous intensity in terms of
candela directly.
PHOTOMETER

12. 1. DEFINE LUMINOUS INTENSITY.
2. WHAT IS THE SI UNIT OF LUMINOUS INTENSITY?
3. DEFINE ONE CANDELA?
4. WHICH INSTRUMENT IS USED TO MEASURE LUMINOUS
INTENSITY?
ASSIGNMENT