JAMB Physics Past Questions & Answers - Page 249

1,241.

What type of reaction is represented by the following scheme? \( ^2 _1X \) + \( ^{2} _{1}Y \) + \( ^{3} _{2}Z \) + \( ^{1} _{0}n \) + energy

A.

Fusion reaction

B.

Fission reaction

C.

Chain reaction

D.

Radioactive decay

Correct answer is A

No explanation has been provided for this answer.

1,242.

A galvanometer of resistance 20\(\Omega\) is to be provided with a shunt that \(\frac{1}{10}\) of the whole current in a circuit passes through the galvanometer. The resistance of the shunt is

A.

2.00\(\Omega\)

B.

2.22\(\Omega\)

C.

18.00\(\Omega\)

D.

18.22\(\Omega\)

Correct answer is B

\(\frac{1}{10}\)I x 20 = \(\frac{9}{10}\)I x Rs

Rs = 2.22\(\Omega\)

1,243.

When two parallel wires carry currents in opposite directions, the force on either wire is

A.

away from the other wire

B.

zero, because the currents cancel each other

C.

twice as much as when the currents are in the same direction

D.

towards the other wire

Correct answer is A

No explanation has been provided for this answer.

1,244.

The direction of the magnetic field at a point in the vicinity of a bar magnet is

A.

always towards the north pole of the magnet

B.

always away from the south pole of the magnet

C.

along the line joining the point to the neutral point

D.

in the direction the north pole of a compass needle would point

Correct answer is D

No explanation has been provided for this answer.

1,245.

A current of 0.5A flows through a resistor when connected to a 40-V battery. How much energy is dissipated in 2 minutes?

A.

1200J

B.

1500J

C.

2400J

D.

96000J

Correct answer is C

Electrical energy = IVT

= 0.5 x 40 x 2 x 60

= 2400J