Which one of the following combinations is the correct ascending order of electromagnetic waves in terms of wavelength?

1. Gamma-rays, visible light, microwaves
2. Microwaves, visible light, gamma-rays
3. Gamma-rays, microwaves, visible light
4. Microwaves, gamma-rays, visible light

For a lever, a graph is plotted with load on Y-axis and effort on X-axis. Which of the following represents the slope of the graph?

1. Mechanical advantage
2. Velocity ratio
3. $\dfrac{1}{\text {Velocity ratio}}$
4. $\dfrac{1}{\text {Mechanical advantage}}$

A ray of light is incident normally on a face of an equilateral prism. The ray gets totally reflected at the second refracting surface. The total deviation produced in the path of the ray is:

1. 30°
2. 60°
3. 90°
4. 120°

In a closed circuit containing a bulb and a cell, the electromotive force (ε) and the terminal voltage (V) is related as.

(Given I is current and r is internal resistance.)

1. V = ε + Ir
2. V = ε – Ir
3. V = ε ÷ Ir
4. V = ε × Ir