JAMB Physics Past Questions & Answers - Page 287

1,431.

A body of weight W N rest on a smooth plane inclined at an angle\(\theta\)o to the horizontal. What is the resolved part of the weight in Newtons along the plane?

A.

W sin\(\theta\)

B.

W cos\(\theta\)

C.

W sec\(\theta\)

D.

W tan\(\theta\)

Correct answer is A

horizontal component = W cos(90o - \(\theta\))

= W sin

1,432.

Which of the following is the most suitable for use as an altimeter?

A.

A mecury barometer

B.

A fortin barometer

C.

A mecury manometer

D.

An aneroid barometer

Correct answer is D

No explanation has been provided for this answer.

1,433.

\(^{27}_{13}Al\) + \(^{1}_{0}n\) \(\Rightarrow\) \(^{24}_{11}Na\) + X

A.

a proton

B.

a gamma ray

C.

a helium particle

D.

an alpha particle

Correct answer is D

\(^{27}_{13}Al\) + \(^{1}_{0}n\) \(\Rightarrow\) \(^{24}_{11}Na\) + \(^{b}_{a}X\)

a + 11 = 0 + 13 \(\Rightarrow\) a = 2

b + 24 = 1 + 27 \(\Rightarrow\) b = 4

\(^{b}_{a}X\) = \(^{4}_{2}\alpha\)

1,434.

After three half lifes, the fraction of a radioactive material that has decayed is

A.

\(\frac{1}{8}\)

B.

\(\frac{1}{3}\)

C.

\(\frac{2}{3}\)

D.

\(\frac{7}{8}\)

Correct answer is D

I = \(\frac{1}{2}\) \(\Rightarrow\) \(\frac{1}{4}\) \(\Rightarrow\) \(\frac{1}{8}\)

Fraction decayed = 1 - \(\frac{1}{8}\)

= \(\frac{7}{8}\)

1,435.

The threshold of frequency for photoelectric effect depends on the

A.

intensity of incident light

B.

frequency of incident light

C.

material of the photocathode

D.

potential difference between the cathode and the anode

Correct answer is C

No explanation has been provided for this answer.