Board Practice Paper – Reflection (Part-1)

class 12 Physics | EDU BRIGHT PAGES

Q1. Which quantity remains unchanged during reflection?

Speed Wavelength Frequency Direction

Answer: Frequency
Frequency depends on the source and does not change on reflection.

Q2. According to Snell’s law, sin i / sin r equals:

Speed of light Refractive index Critical angle Deviation

Answer: Refractive index
Snell’s law defines refractive index as sin i / sin r.

Q3. Total internal reflection occurs when light travels from:

Rarer to denser Denser to rarer Same medium Vacuum to glass

Answer: Denser to rarer
TIR occurs only when light moves from denser to rarer medium.

Q4. At critical angle, angle of refraction is:

0° 45° 90° 180°

Answer: 90°
At critical angle, refracted ray grazes the surface.

Q5. Focal length of a concave mirror is:

Positive Negative Zero Infinite

Answer: Negative
Concave mirror focus lies opposite to incident light.

Q6. If u = –20 cm and v = –40 cm, image is:

Virtual & erect Real & inverted Virtual & inverted Real & erect

Answer: Real & inverted
Negative v indicates real image.

Q7. Angle of minimum deviation depends on:

Angle only Refractive index only Both angle and refractive index Thickness

Answer: Both angle and refractive index.

Q8. Prism deviates light due to:

Reflection Scattering Refraction Interference

Answer: Refraction.

Q9. SI unit of power of lens is:

Metre Centimetre Dioptre Joule

Answer: Dioptre.

Q10. Real image exists without screen because:

Screen forms image Rays converge in space Light reflects back Image becomes virtual

Answer: Rays converge in space.

Q11. Function of screen is to:

Create image Increase size Diffuse rays Absorb light

Answer: Diffuse rays.

Q12. Image is not seen on rough surface because:

Absorption Irregular reflection Refraction Diffraction

Answer: Irregular reflection.

Q13. Image formation requires regular reflection because:

Rays diverge Rays meet at one point Surface thick Scattering

Answer: Rays meet at one point.

Q14. Thick lenses produce coloured images due to:

Reflection Dispersion Absorption Diffraction

Answer: Dispersion.

Q15. Simple microscope magnifies because:

Image is real Angular size increases Light intensity increases Lens is thick

Answer: Angular size increases.