Loading [MathJax]/jax/output/HTML-CSS/jax.js

JAMB Physics Past Questions & Answers - Page 160

796.

The external parts of an object can be measure accurately through the use of which scientific instrument?

Micrometer screw gauge

Vernier Caliper

Meter rule

None of the instrument

View answer & explanation

Correct answer is B

Vernier calliper is used to measure the internal and external diameter of an object

797.

What is the relationship mechanical advantage (MA) velocity Ratio (V.R) and efficiency with percentage?

e = M.A/V.R × 100 %

M.A = E.V.R

V.R = 1 ÷ sin θ M.A

M.A = 1/E × 100%

View answer & explanation

Correct answer is A

The relationship between M.A, V.R, e and 100% can be written as

e = M.A/V.R × 100 %

i.e E/100 = M.A/V.R

= L ÷ E/x ÷ y = Ly/Ex

E/100 = Ly/Ex

798.

Electrons were discovered by

James Chadwick B.

J.J Thompson

Sir Isaac Newton

Charles Newton

View answer & explanation

Correct answer is B

J.J. Thompson discovered ELECTRONS

799.

Mr. F. Abioye observed his image through a plane mirror, kept at a distance 4.7m away from him in his room. At what distance is the image found from Abioye's eye?

9.4m

7.5m

5.7m

6.9m

View answer & explanation

Correct answer is A

As object and image are usually at equal distance apart from the mirror /p>

Distance between Abioye (a) and hip image (I) = AI

i.e. AI = 4.7 + 47

= 9.4m

800.

Calculate the gravitation force of attraction between two planets of 10²⁴kg and 10²⁷kg separated by a distance of 10²⁰meters.

6.67N

6.56N

7.5N

8.6N

View answer & explanation

Correct answer is A

F = (Gm₁m₂) ÷ r²

M₁ = 10₂₄Kg, M₂ = 10²⁷Kg , r = 10²

(Note: the gravitational constant of G = $6.67 × 10^{ 7ndash; 11}$ $Nm^2/Kg^2$

F = \( (6.67 × 10^{– 11 + 24 + 27)} 10^40 = 6.67 × (10^40 ÷ 10^40)

= 6.67N

f = 6.67N