Physics Past Questions and Answers

In which of the following devices is the principle of photoelectric effect not applicable?

A Close-circuit television camera
B Burglar alarm
C Solar cells
D Periscope

Question 3192:

Which of the following statements about X-rays is not correct? They

A Are electromagnetic waves
B Can be used to study crystal lattice
C Can destroy living cells
D Are produced from the nucleus of an atom

Question 3193:

A radioactive substance has a half-life of 3 days. If a mass of 1.55g of this substance is left after decaying for 15 days, determine the original value of the mass

A 49.6g
B 37.2g
C 24.8g
D 12.4g

Question 3194:

Which of the following representations is correct for an atom X with 28 electrons and 30 neutrons?

A \(^{30}_{28} X\)
B \(^{28}_{30} X\)
C \(^{58}_{30} X\)
D \(^{58}_{28} X\)

Question 3195:

In an experiment using a converging lens to produce real images on a screen, the linear magnification m, is plotted against the image distance v, as illustrated in the diagram below. The distance OP represents the

A Focal legth of the lens
B Thickness of the lens
C Radius of curvature of the lens
D Diameter of the lens