What is the difference between a CFL and an LED lamp ? 1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material. 2. The average life span of a CFL is much longer than that of an LED lamp. 3. A CFL is less energy-efficient is compared to an LED lamp. Which of the statements given above is/ are correct?

Which of the following statements are correct about the electrical resistance and resistivity of a wire? 1. Both quantities depend on the area of cross-section of the wire 2. Both depend on the tempe…

The potential difference between the two end terminals of an electric heater is 220 V and the current through it is 0.5 A. What would be the current through the heater if the potential difference acr…

Given below are two statements, in which one is labelled as Assertion (A) and the other as Reason (R): Assertion (A) : A person travelling in a car with closed glass windows and doors is safe from th…

Two conducting wires of the same material and of equal lengths and equal diameters are first connected in parallel and then in series in a circuit across the same potential difference. The ratio of h…

Which of the following statements correctly 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 cha…