12th Physics Chapter 6 Important – 2 Marks

• 1. State Snell‟s law/ law of refraction.

• 2. What is principle of reversibility?

• 3. Why do stars twinkle?

• 4. Explain the reason for the glittering of diamond. (MAR 23)

• 5. What are mirage and looming?

• 6. What is Snell‟s window?

• 7. What is dispersion?

• 8. How are rainbows formed?

• 9. What is Rayleigh‟s scattering?

• 10. Why does sky appear blue? (AUG 21, JUNE 24)

• 11. What is there as on for reddish appearance of sky during sun set and sunrise? (JUNE 23)

• 12. Why do clouds appear white?

• 13. What are Paraxial Rays and Marginal Rays? (SEP 20)

• 14. Pure water has refractive index 1.33. What is the speed of light through it? (Example 6.5) (JULY 22)

• 15. The angle of minimum deviation for an equilateral prism is 40o. Find the refractive index of the material of the prism. (Model 6.21) (MAY 22)

• 16. If the focal length is 150 cm for a lens, what is the power of the lens?(Example 6.15) (MAR 24)

12th Physics Chapter 6 Important – 3 Marks

• 1. Derive the relation between f and R for a spherical mirror. (MAY 22, JUNE 24)

• 2. What is optical path? (MAR 25) Obtain the equation for optical path and mention what each term represents. (MAR 23)

• 3. What are critical angle and total internal reflection? (AUG 21)

• 4. Obtain the equation for critical angle.

• 5. What is total internal reflection? Give the condition for the total internal reflection takes place. (SEP20)

• 6. Obtain the equation for lateral magnification of thin lens.

• 7. Obtain the expression for apparent depth.

• 8. List out the characteristics of imaged formed by a plane mirror.

• 9. Derive the equation for effective focal length for lenses in contact. (MAR 24)

• 10. Find the ratio of the intensities of lights with wavelengths 500 nm and 300 nm which undergo Rayleigh scattering. (CH-6, EX-10) (JUNE 23)

• 11. Light travels from air into a glass slab of thickness 50 cm and refractive index 1.5. What is the speed of light in the glass slab and what is the time taken by the light to travel through the glass slab? (Exam- 6.6) (JULY 22)

12th Physics Chapter 6 Important – 5 Marks

• 1. Derive the mirror equation and the equation for lateral magnification. (MAR 20, JUNE 24)

• 2. Describe the Fizeau‟s method to determine the speed of light. (JULY 22, MAR 23,25)

• 3. Obtain lens maker‟s formula and mention its significance. (SEP 20,AUG 21, MAY 22)

• 4. Derive the equation for angle of deviation produced by a prism and thus obtain the equation for refractive index of material of the prism. (SEP 20, MAR 24)

• 5. What is dispersion? Obtain the equation for dispersive power of a medium. (JUNE 23)

• 6. Derive the equation for acceptance angle and numerical aperture of optical fibre.

• 7. Derive the equation for refraction at single spherical surface.

• 8. What is Snell’s Window? Obtain an expression for the radius of illumination.