Physics Past Questions and Answers

In a series R-L-C circuit, R = 10\(\Omega\), \(X_{c}\)= 4\(\Omega\) and \(X_{L}\) = 9\(\Omega\). The impedance of the circuit is

A 4.1\(\Omega\)
B 5.0\(\Omega\)
C 10.8\(\Omega\)
D 11.2\(\Omega\)

Question 4067:

A student uses two compass needles to investigate the magnetic field around a bar magnet. Which of the following diagrams show the correct directions of the needles?

Question 4068:

Which of the following is emitted in a process of natural radioactivity?

A \(\alpha\)- particles and \(\beta\)- particles
B \(\alpha\)- particles and X-rays
C \(\beta\)- particles and X-rays
D \(\lambda\)- rays and X-rays

Question 4069:

In which of the following situations is photoelectric effect employed?<br/>I. Automatic devices for switching on light at dusk<br/>II. Automatic doors in departmental stores<br/>III. Automatic devices for switching on air conditioners<br/>IV. Automatic voltage stabilizers

A I, II and IV only
B I, III and IV only
C III and IV only
D I and II only

Question 4070:

Which of the following radiations has the longest wavelength?

A Gamma ray
B Radio wave
C Infrared ray
D X-ray