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#### Light Two Marks Questions

8th Standard EM

Reg.No. :
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Science

Time : 00:45:00 Hrs
Total Marks : 20
10 x 2 = 20
1. The radius of curvature of a spherical mirror is 20 cm. Find its focal length.

2. Focal length of a spherical mirror is 7 cm. What is its radius of curvature?

3. If two plane mirrors are inclined to each other at an angle of 90°, find the number of images formed.

4. Speed of light in air is 3 × 108 ms-1 and the speed of light in a medium is 2 × 108 ms-1. Find the refractive index of the medium with respect to air.

5. Refractive index of water is 4/3 and the refractive index of glass is 3/2. Find the refractive index of glass with respect to the refractive index of water.

6. Which mirror is used in solar cookers and solar water heaters?

7. Who constructed first parabolic mirrors in the form of reflector?

8. Who founded the Book "On Burning Mirrors"?

9. What is the value of velocity of light in air?

10. When will the concave mirror form a real and inverted image?