Waec Physics 1998 Past Questions and Answers

Question 51:

• WAEC 1998

An electron is accelerated from rest through a potential difference of 70kV in a vacuum. Calculate the maximum speed acquired by the electron (electronic charge = -1.6 x 10^-19; mass of an electron = 9.1 x 10^-31kg)

A. 3.00 x 10⁸ms^-1
B. 2.46 x 10⁸ms^-1
C. 1.57 x 10⁸ms^-1
D. 1.32 x 10⁸ms^-1
E. 1.11 x 10⁸ms^-1

Question 52:

• WAEC 1998

When light from a source is sent through a gas. i. certain wavelengths are absorbed. ii. a dark line is left. Which of the following is/are correct?

A. I only
B. Iii only
C. I and ii only
D. I and iii only
E. Ii and iii only

Question 53:

• WAEC 1998

The diagram above represents a section of a pair of vernier calipers. The reading on the instrument is

A. 5.22cm
B. 5.24cm
C. 5.26
D. 5.35

Question 54:

• WAEC 1998

The process of increasing the energy of an atom via inelastic collision with an electron is known as

A. Ionization
B. Excitation
C. Field emission
D. Photoemission
E. Thermonic emission

Question 55:

• WAEC 1998

A radioactive nuclide of proton number X emits a \(\beta\)-particle to form a new nuclide to proton number Y. The correct equation relating X and Y is

A. X = Y - 1
B. X = Y + 1
C. X = 1 - Y
D. X = \(\frac{1}{y}\)
E. X = Y