Q. The frequency of an alternating current is 3 Hz. It implies that -
1) there are 6 cycles/s
2) there are 3 cycles/s
3) there are 2 cycles/s
4) there is only 1 cycle
Q. Which one of the following is a chemical change?
1) Dissolving sugar in water
2) Melting of ice
3) Crystallization
4) Milk turning sour
Q. Refining of petroleum is carried out using which one of the following techniques?
1) Evaporation
2) Fractional distillation
3) Separating funnel
4) Sublimation
Q. Which one of the following is not a solution?
1) Alloy
2) Milk
3) Air
4) Sugar
Q. The electric field lines from an isolated positively charged conducting sphere are -
1) tangential to the conducting surface
2) at right angles to the conducting surface and toward the center of the sphere
3) at any angle to the conducting surface
4) at right angles to the conducting surface and outwards from the center of the sphere
Q. An electric wire of resistance 50 Ω (ohms) is cut into five equal wires. These wires are then connected in parallel. What is the equivalent resistance of this combination?
1) 2 Ω
2) 10 Ω
3) 0.5 Ω
4) 5 Ω
Q. Which of the following statements correctly explains/explain the existence of a positive force between two electric charges?
1. Both the charges are positive.
2. Both the charges are negative.
3. Both the charges are oppositely charged.
Select the correct answer using the code given below -
1) Only l
2) Only 2
3) Only 1 and 2
4) All 1, 2 and 3
Q. Evaporation from the surface of a given liquid takes place more rapidly when -
1) the temperature is high and the surface area of the liquid is large
2) the temperature is low and the surface area of the liquid is large
3) the temperature is low and the surface area of the liquid is small
4) the temperature is high and the surface area of the liquid is small
Q. The specific latent heat of vaporization of a substance is the quantity of heat needed to change unit mass from -
1) liquid to vapour with a change in temperature
2) liquid to vapour without a change in temperature
3) vapour to liquid without a change in temperature
4) vapour to liquid with a change of temperature
Q. What is the mass of a material, whose specific heat capacity is 400 J/(kg °C) for a rise in temperature from 15°C to 25°C, when heat received is 20 kJ?
1) 0.1 kg
2) 1 kg
3) 10 kg
4) 5kg