JAMB Physics Past Questions & Answers - Page 264

1,316.

Which of the following is TRUE of the particles emitted in radioactive disintegration?

A.

the beta particle is the helium nucleus H

B.

the alpha particle is lighter than the beta particle

C.

the alpha particle is deflected more than the beta particle in a magnetic field

D.

the beta particle is deflected more than the alpha particle in a magnetic field

Correct answer is D

No explanation has been provided for this answer.

1,317.

When a radiation strikes a metal surface, electrons may be ejected from the metal. The maximum kinetic energy which may be acquired by an ejected electron depend on the

A.

intensity of the radiation

B.

source of the radiation

C.

wavelength of the radiation

D.

detection device of the electron

Correct answer is C

The maximum kinetic energy of an emitted electrons is independent of the intensity of the incident light but proportional to the frequency ( wavelength) of incident light. increasing the intensity of light only increases the number of photo-electrons

1,318.
1,319.

An ammeter of resistance 1.0\(\Omega\) has a full-scale deflection of 50mA. Determine the resultant full-scale deflection of the meter when a shunt of 0.0111\(\Omega\) is connected across its terminals.

A.

400mA

B.

450mA

C.

500mA

D.

550mA

Correct answer is A

V = 0.1 x 50 x 10-3 = 5 x 10-3volts

RT = \(\frac{0.1 \times 0.0111}{0.1 + 0.0111}\)

= 9.99 x 10-3\(\Omega\)

V = IR \(\Rightarrow\) I

= \(\frac{5 \times 10^{-3}}{9.9 \times 10^{-3}}\)

= 0.5A ; = 500mA

1,320.

A calibrated potentiometer is used to measure the e.m.f. of a cell because the

A.

internal resistance of a cell is small compared with that of the potentiometer

B.

potentiometer has a linear scale

C.

potentiometer takes no current from the cell

D.

resistance of the potentiometer is less than that of a voltmeter

Correct answer is C

No explanation has been provided for this answer.