Physics Past Questions and Answers

An ammeter with a full scale deflection of 10mA has an internal resistance 0.5\(\Omega\). calculate the resistance of the shunt required to adapt it to read up to 3A

A 0.0167\(\Omega\)
B 0.0130\(\Omega\)
C 0.0250\(\Omega\)
D 0.1000\(\Omega\)

Question 1437:

The resistivity, \(\mathit{P}\), of a material of length l, cross-sectional area A, resistance R, is given by the equation

A \(\mathit{P} = \frac{RA}{l}\)
B \(\mathit{P} = \frac{l}{RA}\)
C \(\mathit{P} = \frac{Rl}{A}\)
D \(\mathit{P} = \frac{R}{Al}\)

Question 1438:

A wire of length 30cm is moved with a speed of 2ms^-1 at right angles to a magnetic field of flux density 0.4T. calculate the emf induced in the wire

A 0.15V
B 0.24V
C 2.70V
D 24.00V

Question 1439:

Which of the following practices will lead to losses in electrical power transmission?

A Using transmission cables of large diameter
B Transmitting at high voltage and low current
C Transmitting at relatively low voltage and high current
D Using a set-up transformer at the production end

Question 1440:

For photoelectric emission, the threshold frequency is the

A Maximum frequency of incident radiation that will eject elecrons
B Minimum fraquency of incident radiation required to eject elecrons
C Frequency which results in the emission of the greater number of electrons
D Fraquency whch impacts greatest kinetic energy to emitte electrons