Two identical waves traveling in the same direction are superimposed. What should be the phase difference between the waves for maximum destructive interference to occur?

• A. 20°
• B. 45°
• C. 180°
• D. 225°

The average kinetic energy of the molecules of a perfect gas is directly proportional to the

• A. pressure exerted by the gas
• B. volume of the gas molecule
• C. kelvin temperature of the gas
• D. celcius temperature of the gas

Which of the following indicates the correct sequence of steps taken in charging a gold-leaf electroscope by induction? l. Removing the ebonite rod ll. Bringing a negatively charged ebonite rod close to the cap III. Earthing the cap IV. Disconnecting the earthing

• A. III, II, I and IV
• B. II, I, III and IV
• C. III, IV II and I
• D. II, III, IV and I

A plane inclined at angle \(\theta\) has a velocity ratio of 10 : 1. The inclination of the plane to the horizontal is given by

• A. tan\(\theta\) = \(\frac{1}{10}\)
• B. cot\(\theta\) = \(\frac{1}{10}\)
• C. cos\(\theta\) = \(\frac{1}{10}\)
• D. sin\(\theta\) = \(\frac{1}{10}\)

I. A liquid boils when its saturated vapor pressure is equal to the external pressure II. Dissolved substances in pure water lead to an increase in the boiling point. III. When the external pressure is increased, the boiling point increases. IV. Dissolved substances in pure water decreases the boiling point Which of the above combinations are peculiarities of the boiling point of a liquid?

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

A uniform light beam XZ is Hinged at X and kept in equilibrium by the forces T and F as shown in the diagram below. if XO = 20m and OY = 30cm, express T in terms of F

• A. T =2?3/3
• B. T= 2F
• C. T = 5V3F/3
• D. T = 5F

In the figure, the value of R is

• A. 3
• B. 6
• C. 4
• D. 5

Tha mass of a proton is approximately equal to that of

• A. an α-particle
• B. a β-Particle
• C. a neutron
• D. an electron

A converging lens of focal length 15cm is used to obtain a real image magnified \(1\frac{1}{2}\) times. Calculate the distance of the image from the lens?

• A. 37.5cm
• B. 22.5cm
• C. 15cm
• D. 7.5cm

The advantages of the thermoelectric thermometer include the following characteristics except that it

• A. can measure rapidly changing temperatures
• B. can measure high and low temperature
• C. can measure high and low temperature almost at a point
• D. is fairly sensitive