Question 86:

• JAMB 1979

Which of the following electromagnetic waves has the shortest wavelength?

A. Radio waves
B. X-rays
C. Infra-red
D. Blue light
E. Ultraviolet

Question 87:

• JAMB 1979

All the heat generated in a 5 ohms resistor by 2A flowing for 30 seconds is used to evaporate 5g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?

A. 120J
B. 60Jg^-1
C. 120Jg^-1
D. 1500J
E. 1500Jg^-1

Question 88:

• JAMB 1979

The speed of light in air is 3 x 10⁸ms^-1. If the refractive index of light from air-to-water is \(\frac{4}{3}\), then which of the following is the correct value of the speed of light in water?

A. 4 x 10⁸ms^-1
B. 2.25 x 10⁸ms^-1
C. \(\frac{4}{9}\) x 10⁸ms^-1
D. 2.25 x 10²ms^-1
E. 4.33 x 10⁸ms^-1

Question 89:

• JAMB 1979

On which of the following is the operation of a moving coil galvanometer based?

A. Magnetic effect of electric current
B. Electromagnetic induction
C. Chemical reaction produced by electricity
D. Force on current carrying conductor in a magnetic field
E. Electrical energy and power

Question 90:

• JAMB 1979

A body is released from rest and allowed to fall freely from a given height under gravity. The kinetic energy at its half-way point is

A. A little above half of its initial energy
B. A little below half of its initial energy
C. A half of its initioal energy
D. A little above its initial energy
E. A little below its initial energy