Physics: Electric Potential and Potential Difference

UNIVERSITY ENTRANCE EXAMINATION

PHYSICS

Duration

: 2 hours

Please read the following instructions carefully.
1.

This paper is made up of 50 Multiple-Choice questions and comprises ELEVEN
(11) printed pages.

2.

Do not write on the question paper.

3.

Answer all questions and indicate your answers on the answer sheet provided.
Marks will not be deducted for wrong answers.

4.

Do not take any paper, including the question paper or unused answer sheets, out of the examination hall.

1

Multiple-Choice Questions
Answer all questions in this section.

1.

The mass of an isotope of uranium

238
92

U is 238.05 g mol–1. Its density is 19.1

g cm–3 at room temperature. Which of the following is closest to the number of 238U atoms in 1 cm3 of this isotope?
92
A
B
C
D
E

2.

2.53x1021
3.29x1022
4.83x1022
6.02x1023
7.51x1024

An isotope of plutonium

239
94

Pu decays by alpha emission.

Which of the

following is the decay product?
243
A
96 Cm
B

235
94

Pu

C

239
93

Np

D

235
92

U

E

234
90

Th

3.

A compact disc of diameter 120 mm is spinning at a speed of 500 revolutions per minute. Which of the following is closest to the linear speed of the outer edge of the disc?
A
0.50 m s–1
B
1.0 m s–1
C
1.6 m s–1
D
3.1 m s–1
E
60 m s–1

4.

A steel wire is stretched and clamped between two fixed points that are spaced 1.0 m apart. Which of the following is closest to the fundamental wavelength that can exist on this wire?
A
B
C
D
E

5.

0.25 m
0.50 m
1.0 m
2.0 m
4.0 m

A thin converging lens of focal length 20 cm is used to shape light from a lamp filament into a parallel beam. Which of the following is closest to the required distance between the lamp filament and the lens?
A
B
C
D
E

5.0 cm
10 cm
20 cm
40 cm
80 cm
2

6.

A metallic sphere of radius 1.0 cm is charged with 1.0x109 electrons in air.
Which of the