Question Library — KalmiPrep by Kalmitech

Physics WAEC / WASSCE 1992 Electricity and Magnetism

What is the electric potential at a point distance r from a proton of charge q placed in a medium of permittivity εo?

A

q2/4πεor2

B

q/4πεor2

C

q2/4πεor

D

q/4πεor

E

4πεoq2r

medium Difficulty

Physics WAEC / WASSCE 1992 Electricity and Magnetism

The diagram above shows the magnetic field around a bar magnet which has its N-pole pointing north. The neutral points in the field are likely to occur at

Attached Figure / Diagram

A

1 and 2

B

3 and 4

C

5 and 6

D

7 and 8

E

9 and 10

medium Difficulty

Physics WAEC / WASSCE 1992 Electricity and Magnetism

A negatively charged rod is brought near the cap of a gold-leaf electroscope. The cap is earthed momentarily while the rod is near to it. The rod is then removed. Which of the following is correct?

A

The cap will be positively charged and the negatively charged leaves will diverge

B

The cap will be negatively charged and the positively charged leaves will diverge

C

The cap and the leaves will be positively charged

D

The cap and the leaves will be negatively charged.

E

The leaves will not diverge because the cap has been earthed.

medium Difficulty

Physics WAEC / WASSCE 1992 Electricity and Magnetism

Calculate the length of a constantan wire of cross- sectional area 4 π x 10-8m2 and resistivity 1.1 x 10-6 Ω m required to construct a standard resistor of resistance 21 Ω. [Take π = 22/7]

A

0.42m

B

2.40 m

C

6.25 m

D

183.75 m

E

590.00 m

medium Difficulty

Physics WAEC / WASSCE 1992 Electricity and Magnetism

A stream of alpha particles is projected into an electric field between two plates X and Y as shown in the diagram above. Which of the following is correct? The particles are

Attached Figure / Diagram

A

accelerated and they continue in a straight line

B

directionally reversed at the end of the plates

C

deflected towards plate Y

D

attracted by both plates

E

deflected towards plate X.

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

The angle between the direction of the earth's magnetic field and the horizontal is called the

A

angle of deviation

B

magnetic declination

C

magnetic meridian

D

angle of dip

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

When an ebolite rod is rubbed with fur, it has

A

no charge at all

B

a negative charge

C

a positive charge

D

negative and positive charges

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

A wire of length 15m made of a material of resistivity 1.8 x 10-6\(\Omega\)m has a resistance of 0.27\(\Omega\). Determine the area of the wire

A

1.5 x 10-4m2

B

1.0 x 10-4m2

C

2.7 x 10-5m2

D

7.3 x 10-6m2

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

A 5-v battery is connected across the plates of a 2.0\(\mu\)F uncharged parallel plate capacitor. The charge on the capacitor after a long time is

A

2.5\(\mu\)C

B

10.0\(\mu\)C

C

20.0\(\mu\)C

D

50.0\(\mu\)C

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

The heat produced in a conductor carrying an electric current is

A

inversely proportional to the current and the resistance

B

directly proportional to the current, resistance and the time

C

inversely proportional to of the resistance, current and the time

D

directly proportional to the square of the current, the resistance and the time

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

The maximum permissible current through a galvanometer G of internal resistance 10\(\Omega\) is 0.05A. A resistance R is used to convert G into a voltmeter with a maximum reading of 100V. Find the value of R and how it is connected to G

A

20,000 ohms in parallel

B

19,990 ohms in series

C

1990 ohms in series

D

100 ohms in series

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

In A.C circuit theory, the root means square (r.m.s) current, Irms and the peak (maximum)current Io are related by

A

Io = \(\frac{I_rms}{\sqrt{2}}\)

B

Irms = \(\frac{I_o}{\sqrt{2}}\)

C

Irms = \(\frac{\frac{I}{I_o}}{\sqrt2}\)

D

Irms = \(\frac{I_rms}{\sqrt{2}}\)

medium Difficulty

Physics UTME / JAMB 1992 Electricity and Magnetism

The diagram above shows a meter bridge in which two of thee arms contain resistances R and 2Ω. A balance point is obtained at 60cm from the left end , calculate the value of R

Attached Figure / Diagram

A

1.2Ω

B

1.3Ω

C

3.0Ω

D

6.0Ω

medium Difficulty

Physics UTME / JAMB 1991 Electricity and Magnetism

Which of the following statements is CORRECT about the earth's magnetic field?

A

the angle of dip is the angle which a freely suspended magnet makes with the vertical

B

the angle of declination is the angle between the magnetic meridian and the geographic meridian

C

the angle of declination is the angle which a magnetic compass makes with the magnetic meridian

D

the angle of inclination is the difference between the angle of dip and the angle of declination

medium Difficulty

Physics UTME / JAMB 1991 Electricity and Magnetism

An insulated rod when rubbed with a material acquires

A

a negative charge if it is made of glass and rubbed with silk

B

no charge if it is made of glass and rubbed with fur

C

no charge if it is made of copper and rubbed with silk

D

a positive charge if it is made of copper and rubbed with fur

medium Difficulty