2015 - JAMB Physics Past Questions and Answers - page 1

Ray – a beam of light or radiation

XL = WL = 2πFL (w = 2πf)

XL = reactance inductor (S.I unit Ω)

L = inductance (L) in Henry

XL = 1Ω, f = 50/π, L = ?

1 = 2× π × 50/π × L

1 = 100L

i.e. 100L = 1

L = 1/100

0.01H

∴ Inductance (L) of a inductor = 0.01H

Stroboscope is a scientific instrument used to make a wave appears stationary when used

In an inelastic collision, linear momentum is conserved and energy is decreased

Momentum and kinetic energy are conserved in elastic collision

Note:The principle of floatation states that a floating body displaces its own weight of the fluid or which its float.

For object to sink weight of the object (W) > upthrust of the fluid (v) i.e. w > u

(i.e. weight of the body (or object) mass of the fluid)

Formula for general gas law

V × 1/T × P

N [(PV) ÷ T] = K is constant

The appearance of pool of water on road surfaces is called MIRAGE

His observation show that light from the sun ray refracted through a layer of hot air(layer) which is closed to the ground, passes from a hot air layer to the cold layer

Sun are self luminous source

Moon is a non – luminous

Note: moment of a couple = force × length (fL)

The tangential force is actingin an opposite direction alongside its length

i.e f1 L1 = f2L2

f2L2 − f1 L1 = 0(i.e Zero)

A vector quantity has both magnitude and direction