Physics Questions and Answers
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
i only
ii only
i and ii only
ii and iii only
Correct answer is A
No explanation has been provided for this answer.
39.0\(\Omega\)
122.5\(\Omega\)
245.0\(\Omega\)
39000.0\(\Omega\)
Correct answer is C
XL = 2\(\pi\)FL
= 2 x 3.142 x 30 x 10-3 x 1.3 x 103
= 245\(\Omega\)
The primary aim in high tension transmission is to
minimize electrical energy losses due to heat production
increase the rate of energy transfer by using high voltage
increase the current in the wire
generate electricity at high current and low voltage
Correct answer is A
No explanation has been provided for this answer.
Which of the following devices may be used to step up the voltage in a d.c. circuit?
a step-up transformer
a d.c. generator
a wattmeter
an induction coil
Correct answer is D
An induction coil is a transformer for producing high-voltage alternating current from a low-voltage direct current, consisting essentially of two concentric coils with a common soft-iron core, a primary coil with relatively few windings of heavy wire, and a secondary coil with many turns of fine wire. Excitation of the primary coil by rapidly interrupted or variable current induces high voltage in the secondary coil.
A 40-W instrument has a resistance of 90\(\Omega\). On what voltage should it be operated normally?
60V
150V
225V
3600V
Correct answer is A
P = \(\frac{V}{R}\)
V = \(\sqrt{PR}\)
V = \(\sqrt{40 \times 90}\)
= 60V