Waec Physics 2017 Past Questions and Answers

Question 41:

• WAEC 2017

A transformer connected to a 240\(V_{r.m.s}\) has 3000 turns in its primary coil and 500 turns in its secondary coil. Calculate the output voltage.

A. 4000V
B. 400V
C. 40V
D. 4V

Question 42:

• WAEC 2017

A lamp rated 100W, 240V is lit for 5hours. Calculate the cost of lighting the lamp if 1kWh of electrical energy cost N5.

A. N2.50
B. N3.20
C. N6.50
D. N9.60

Question 43:

• WAEC 2017

A battery of e.m.f 3.0V is connected across a potentiometer wire AB of length 10\(\Omega m^{-1}\) as illustrated in the diagram above. If the jockey J makes contact at the 30cm mark, determine the resistance of length AJ and voltage across AJ.

A. 3.0\(\Omega\); 0.9V
B. 3.0\(\Omega\); 3.0V
C. 3.3\(\Omega\); 0.3V
D. 3.3\(\Omega\); 9.0V

Question 44:

• WAEC 2017

The main reason why a.c. is transmitted at very high voltage and low current is that

A. Flows faster through the conductor
B. Can be stepped down
C. Is cheaper to generate
D. Reduces heat loss

Question 45:

• WAEC 2017

The diagram above illustrates two charged bodies, X and Y seperated by a distance r. Each body has charge q and mass m. Which of the following statements about the electrostatic force \(F_{e}\) and fravitational force \(F_{g}\) acting between the bodies is correct?

A. \(F_{e}\) is attraction while \(F_{g}\) is repulsion
B. Both \(F_{e}\) and \(F_{g}\) are that of repulsion
C. Both \(F_{e}\) and \(F_{g}\) is that of attraction
D. \(F_{e}\) is repulsion while \(F_{g}\) is attraction