### Physics Past Questions

26

A 3000W electric cooker is to be used on a 200V mains circuit. Which of the fuses below can be used safely with the cooker?

• A. 2A
• B. 5A
• C. 10A
• D. 20A
JAMB 1999
27
A galvanometer has a resistance of 5Ω. By using a shunt wire of resistance 0.05Ω, the galvanometer could be converted to an ammeter capable of reading 2Amp. What is the current through the galvanometer?
• A. 2mA
• B. 10mA
• C. 20mA
• D. 25mA
JAMB 1999
28
In fleming's right-hand rule, the thumb, the forefinger and the middle finger if held mutually at right angles represent respectively, the
• A. motion, the field and the induced current
• B. induced current, the motion and the field
• C. field, the induced current and the motion
• D. induced current, the field and the motion
JAMB 1999
29
At what frequency would a 10H inductor have a reactance of 2000Ω?
• A. π/200Hz
• B. π/100Hz
• C. 100/πHz
• D. 100πHz
JAMB 1999
30
The core of an efficient transformer should consist of laminated pieces of metal in order to
• A. increase the heat produced by increasing the eddy current
• B. increase the heat produced by reducing the eddy current
• C. reduce the heat produced by increasing the eddy current
• D. reduce the heat produced by reducing the eddy current
JAMB 1999