2010 - JAMB Physics Past Questions and Answers - page 3

The retina is light sensitive layer living the inner wall of the eye where image is formed. in the camera, image is formed on a light sensitive film.

(1)/v + (1)/u = (1)/f

(1)/v + (1)/15 = (1)/5

(1)/v = (1)/5 - (1)/15 = (3 - 1)/15 = (2)/15

∴ v = (15)/2 = 7.5 cm

magnification = (v)/u = (image size)/object size

(7.5)/15 = (X)/4

∴ image size. X = (7.5 x 4)/15 = 2 cm

Refraction index, n = (real depth)/apparent depth

1.5 = (10)/X

X = (10)/1.5 = 6.67 cm

Concave lens diverges parallel rays of light. A short sighted person has the image formed before the retina,and the rays have to be diverged so that they intersect to form image onto the retina

Dispersion is the splitting of white light into its spectral component colours and is caused by different speed of the colours in the prisma

Since the charged rod is not in contact with the electroscope, the leaves divergence will be induced

H eat generated in a wire carrying current, H = 1² Rt.

so, when voltage is high and current is low heat generated in the wire will be minimal.

Therefore, high voltage and low current prevent overheating of the coil.

R = (Vg)/lg = G, where lg = current through galvanometer

R = resistance of the multiplier

G = resistance of the galvanometer

∴ G = (vg-R)/lg 5(1000/10) - 490 = 500 -490 = 10Ω

Correct Answer: Option E

        Total inductance,L = L<sup>1</sup> + L<sup>2</sup> = m<br />

15 + 5 = 20mH = (20)H/1000

1 = 5A

Energy of inductor, (1)/2 L I²

= (1)/2 X (20)/1000 X 5^-2

= 0.25 J