Jamb Physics 2007 Past Questions and Answers

Question 31:

• JAMB 2007

A blacksmith heated a metal whose cubic expansivity is 6.3 x 10^-6K^-1. The areal expansivity is

A. 2.0 x 10^-6K^-1
B. 2.1 x 10^-6K^-1
C. 4.2 x 10^-6K^-1
D. 6.3 x 10^-6K^-1

Question 32:

• JAMB 2007

The ratio of the coefficient of linear expansion of two metals ^∝₁/_∝[sub]2[/sub] is 3:4. If, when heated through the same temperature change, the ratio of the increase in length of the two metals, ^e₁/_e[sub]2[/sub] is 1:2, the ratio of the original lengths ^l₁/_l[sub]2[/sub] is

A. ⁸/₃
B. ³/₂
C. ²/₃
D. ³/₈

Question 33:

• JAMB 2007

The fundamental frequency of a plucked wire under a tension of 400N is 250Hz. When the frequency is changed to 500 Hz at constant length, the tension is

A. 1600N
B. 400N
C. 160N
D. 40N

Question 34:

• JAMB 2007

Three cells each of e.m.f 1.5 V and internal resistance 2.5Ω are connected as shown in the diagram above. Find the net e.m.f and the internal resistance

A. 1.5V, 7.50Ω
B. 1,5V, 0.83Ω
C. 4.5V, 7.50Ω
D. 4.5V, 0.83Ω

Question 35:

• JAMB 2007

In the diagram above , if the magnetic field points into the paper and the force on a current - carrying conductor points upwards, what is the direction of the current?

A. Upwards
B. Downwards
C. Right
D. Left