List of top Science Questions on Electricity

Which of the following is the commercial unit of electrical energy?

The SI unit of resistance is

The electrical resistivity of silver at 20$^\circ$C is

What will be the resistance of the wire when its length increases?

What do you understand by potential difference ?

The unit of resistivity in a conductor is

In our houses we receive A.C. electric power of 220 V. In electric iron or electric heater cables having three wires with insulation of three different colours – red, black and green are used to draw current from the mains. What are these three different wires called? Name them colourwise. What is the potential difference between the red wire and the black wire? What is the role of the wire with green insulation in case of accidental leakage of electric current to the metallic body of an electrical appliance?

Define the term "potential difference" between two points in an electric circuit carrying current. Name and define its S.I. unit. Also express it in terms of S.I. unit of work and charge.

Study the circuit shown in which two resistors X and Y of resistances 3 Ω and 6 Ω respectively are joined in series, with a battery of 2 V

What do the symbols given below represent in an electric circuit? Write one function of each.

Assertion (A): Food web is a network of several food chains operating in an ecosystem.
Reason (R): Food web decreases the stability of an ecosystem.

In a domestic circuit five LED bulbs are arranged as shown. The source voltage is 220 V and the power rating of each bulb is marked in the circuit diagram. Based on the following circuit diagram, answer the following questions:

(a) State what happens when
(i) key K₁ is closed.
(ii) key K₂ is closed.
(b) Find the current drawn by the bulb B when it glows.
(c) Calculate
(i) the resistance of bulb B, and
(ii) total resistance of the combination of four bulbs B, C, D and E.
OR
(c) What would happen to the glow of all the bulbs in the circuit when keys K₁ and K₂ both are closed and the bulb C suddenly get fused ? Give reason to justify your answer.

Choose the correct alternative by matching the physical quantities in column (B) with the units in column (A): \[ \begin{array}{|l|l|} \hline \textbf{A} & \textbf{B} \\ \hline (1) \text{Ohm} & (ii) \text{Electric resistance} \\ \hline (2) \text{Watt} & (iii) \text{Electric power} \\ \hline (3) \text{Ampere} & (i) \text{Electric current} \\ \hline (4) \text{Volt} & (iv) \text{Electric potential difference} \\ \hline \end{array} \]

Three wires A, B and C are emerging out from the main source of a house. What will be the name, function, and colour of the insulation for each wire?

The resistance of a conductor depends on which factors and how? The resistance of a wire is \( R \). What will be the resistance of the wire when the wire is of double length and half the radius of the same material?

In which of the following wires of domestic electric distribution is the fuse wire connected in series?

In a conductor, 10 ampere of current is flowing. What will be the amount of charge flowing in 2 seconds corresponding to it?

If the units of power, work, and time are represented by \( x_1, x_2, x_3 \) respectively, then which of the following relations is correct?

How many wires are used in domestic electrical circuits? Write the names of each and their colours of insulation.

A refrigerator of 500 watts is used for 12 hours every day. How much kilowatt-hour energy is consumed by the refrigerator for 30 days?

How are voltmeter and ammeter joined on passing current in a resistor?

What is the unit of specific resistance? A resistance of 25 \( \Omega \) is connected to a 12-volt battery. Calculate the heat energy in joules generated per minute.