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  1. The illuminance on a surface is 6 lux and the surface is 4 meters from the light source. What is the intensity of the source?
A96 candelas B. 72 candelas C. 24 candelas

  1. Which of the following is accurate in describing converging and diverging lenses?
ABoth of these types of lenses have the ability to produce upright images.
BDiverging lenses will produce images behind the lens, and converging lenses will produce images in front of the lens.
CBoth of these types of lenses have the ability to produce real images.
DParallel rays converge into a single point at the focal point of a diverging lens, whereas parallel rays diverge at the focal point of a converging lens and spread out.

  1. The light intensity of a source is 100 candelas. The illuminance on a surface is 4 lux. How far is the surface from the source?
A4 meters B. 6 meters C. 5 meters D. 7 meters

Verified Answer :

cheetosticks
  1. Is A 96 candelas

    2. I think it's D, I'm not sure

    3. Is C 5 meters

smmwaite

Answer

1) A. 96 Candelas

2) A. Both of these types of lenses have the ability to produce upright images.

3) C. 5 meters


Explanation

Q1

The formula for calculation the luminous intensity is;

Luminous intensity = illuminance × square radius

Lv = Ev × r²

= 6 × 4²

= 6 × 16

= 96 Candelabra

Q2

For converging lenses, an upright image is formed when the object is between the lens and the principal focus while a diverging lens always forms and upright image.

A. Both of these types of lenses have the ability to produce upright images.

Q3

Luminous intensity = illuminance × square radius

square radius = Luminous intensity/ illuminance

r² = 100/4

= 25

r = √25

= 5 m




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