2008 - JAMB Physics Past Questions and Answers - page 3

Due to rectilinear propagation of light we have ecslipse which occur as a result relative motion of the earth, sun and moon

Magnification = (image height)/object height

= (lenght camera)/object distance from pin-hole

∴(2)/4 = (6)/X

X (4 x 6)/2 = 12 cm

(1)/V + (1)/U = (1)/f

(1)/V + (1)/20 = (1)/10

(1)/V = (1)/10 - (1)/20 = (2 -1)/20 = (1)/20

∴ V = 20 cm

mag = (image height)/object height = (v)/u

(X)/5 = (20)/50

X = 5 cm

Image formed by convex mirror is always erect, virtual and diminished

Real depth and apparent dept is due to refraction

The basic function of microscope is magnification

Angular magnification, M = ((D)/F + 1) where D is least distance of distinct vision

∴ M = ((25)/5 + 1) = -6

The friction between the tanker and air creates charges which the chain conducts to the ground.

Power supplied = IE = 20 X 240 = 4800 W

Power dissipated = IV = 20 X 220 = 4400 W

(Power supplied)/Power dissipated = (4800 W)/4400 W

= (12)/11

Energy consumed = power x time

= (60 W x 10 + 40 W x 5) x 24 h

= (600 W + 200 W ) x 24 h

= 800 W x 24h = 19200 w h

= 19.2 kWh