(a) Define critical angle.

(b) How are anti-nodes created in a stationary wave?

(c) The angle of minimum deviation of an equilateral triangular glass prism is 46.2°. Calculate the refractive index of the glass.

(d) An illuminated object is placed in front of a concave mirror and the position of a screen is adjusted in front of the mirror but no image is obtained on the screen. Give two possible reasons for this observation.

(e) An illuminated object is placed at a distance of 75 cm from a converging lens of focal length 30 cm.

(i) Determine the image distance.

(ii) If the lens is replaced by another converging lens, the object has to be moved 25 cm further away to have its sharp image on the screen. Determine the focal length of the second lens.

fiksoyebola

2 years ago

I disagree with both answers.

okpeguru

2 months ago

(e)(i) Determine the image distance

We use the lens formula:

1/𝑓 = 1/𝑣 + 1/𝑢

Where:

𝑓 = 30 cm 𝑢 = 75 cm

Substitute:

1/30 = 1/𝑣 + 1/75

v = 50cm

Image distance = 50 cm

(e)(ii) Determine the focal length of the second lens

New object distance:
𝑢 = 75 + 25 = 100 cm

The screen position remains the same, so: 𝑣 = 50 cm

Use the lens formula again:

1/𝑓 = 1/𝑣 + 1/𝑢

1/𝑓 = 1/50 + 1/100

𝑓 ≈ 33.3 cm

Focal length of second lens ≈ 33.3 cm

Final Answers Summary

(e) (i): 50 cm
(e) (ii): 33.3 cm

Etim_Bassey

1 year ago

(e) (i) 1u+1v=1f

1v=1f−1u=130−17

= 5−2150=3150
f = 50cm
U = 75 + 25 = 100cm
1u+1v=1f

1100+150=150=150

COLDPARADOX

1 month ago

The definition for antinodes is wrong this is the correct one: Antinodes are created in a stationary wave through constructive interference, where two waves of the same frequency and amplitude, traveling in opposite directions, meet and add together.