Physics Past Questions and Answers

What is the total electrical energy consumed by using an electric cooker rated 1000W for 5 hrs?

A 5.3 x 10³J
B 6.5 X 10³J
C 1.8 X 10⁷J
D 2.3 X 10⁷J

Question 37:

The power dissipated in an a.c. circuit with an r.m.s, current of 5A, r.m.s voltage of 10V and a phase angle of 60^o is

A 25W
B 50W
C 120W
D 125W

Question 38:

The voltage of the domestic electric supply is represented by the equation V = 311 sin314.2t. Determine the frequency of the a.c. supply [\(\pi\) = 3.142]

A 50.0Hz
B 100.0Hz
C 311.0Hz
D 314.2Hz

Question 39:

In a purely inductive circuit, the current

A Lags behind the voltage in phase by 90^o
B Leads the voltage in phase by 90^o
C Is in the same phase with the voltage
D Leads the voltage by 180^o

Question 40:

One of the features of the fission process is that

A Its products are not radioactive
B It leads to chain reaction
C Neutrons are not released
D The sum of the masses of the reactants equals the sum of masses of the products