Cathode rays are

• A. High-energy electromagnetic waves
• B. protons
• C. neutrons
• D. streams of electrons

A lantern gives an image of 3m square of a slide 7.62cm square on a screen. If the screen is 10m from the projection lens of the lantern, calculate the focal length of the lens

• A. 40.3cm
• B. 26.1cm
• C. 24.8cm
• D. 0.7cm

The energy stored in a spring of stiffness constant k = 2000\(Nm^{-1}\) when extended 4cm is

• A. 0.16J
• B. 1.60J
• C. 16.00J
• D. 160.00J

A bob of weight 0.1 N hangs from a massless string of length 50 cm. A variable horizontal force which increase from zero is applied to pull the bob until the string makes an angle of 60o with the vertical. The work done is

• A) 0.500 J
• B) 0.250 J
• C) 0.050 J
• D) 0.025 J

When a water droplet is placed on a freshly cut piece of wood, it spreads out to form a thin layer because the wood is

• A. not at equilibrium with the water
• B. cohesive to water
• C. at equilibrium with the water
• D. adhesive to water

When connected to a mains of 250V, the fuse rating in the plug of an electric device of 1 KW is

• A. 2 A
• B. 3 A
• C. 4 A
• D. 5 A

From the diagram below, if the potential difference across the resistor, capacitor and inductor are 80 v, 110 v, 40 v respectively, the effective potential difference is

• A) 116.3 V
• B) 50.0 V
• C) 230.0 V
• D) 106.3 V

Dry hydrogen is trapped by pellet of mercury in a uniform capillary tube closed at one end. If the length of the column of hydrogen at 27°C is 1.0m, at what temperature will the length be 1.20m?

• A. 22.5°C
• B. 32.4°C
• C. 77.0°C
• D. 87.0°C

The friction which exists between two layers of liquid in relative motion is called

• A. capillarity
• B. surface tension
• C. viscosity
• D. cohension

If the partial pressure of water vapour at 27^°C is 18 mm Hg and the saturated vapour pressure of the atmosphere at the same temperature is 24 mm Hg, the relative humidity at this temperature is?

• A) 25%
• B) 33%
• C) 75%
• D) 82%