Question 1

Q1: Which of the following correctly describes the magnetic field near a long straight wire? (a) The field consists of straight lines perpendicular to the...

Accepted Answer

The correct option is (d) The field consists of concentric circles centred on the wire. Explanation: As described in Section 12.2.1 and demonstrated in Activity 12.5, when an electric current passes through a long straight conductor, it generates a magnetic field around it. The magnetic field lines...

Question 2

Q2: At the time of short circuit, the current in the circuit (a) reduces substantially. (b) does not change. (c) increases heavily. (d) vary continuously.

Accepted Answer

The correct option is (c) increases heavily. Explanation: A short circuit occurs when the live wire and the neutral wire come into direct contact, often due to damaged insulation. This creates a path of very low resistance for the current to flow. According to Ohm's law ($I = V/R$), when the resista...

Question 3

Q3: State whether the following statements are true or false. (a) The field at the centre of a long circular coil carrying current will be parallel straig...

Accepted Answer

(a) True. A long circular coil carrying current is a solenoid. As stated in Section 12.2.4, the magnetic field lines inside a current-carrying solenoid are in the form of parallel straight lines. This indicates that the magnetic field is uniform and strong inside the solenoid. (b) False. In domestic...

Question 4

Q4: List two methods of producing magnetic fields.

Accepted Answer

Based on the chapter, two methods of producing magnetic fields are: 1.  Using a Permanent Magnet: A permanent magnet, such as a bar magnet, has a natural magnetic field in the region surrounding it. This field can be detected by the force it exerts on other magnetic materials or a compass needle. 2....

Question 5

Q5: When is the force experienced by a current-carrying conductor placed in a magnetic field largest?

Accepted Answer

The force experienced by a current-carrying conductor placed in a magnetic field is largest when the direction of the electric current is perpendicular (at a right angle, or $90^\circ$) to the direction of the magnetic field. As mentioned in Section 12.3, experiments show that the displacement of th...

Question 6

Q6: Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is...

Accepted Answer

To determine the direction of the magnetic field, we can use Fleming's Left-Hand Rule. First, we need to identify the directions of the current and the force. 1.  Direction of Current: The electron beam moves from the back wall to the front wall. By convention, the direction of electric current is t...

Question 7

Q7: State the rule to determine the direction of a (i) magnetic field produced around a straight conductor-carrying current, (ii) force experienced by a c...

Accepted Answer

(i) Magnetic field produced around a straight conductor-carrying current: The direction of the magnetic field is determined by the Right-Hand Thumb Rule. According to this rule, if you imagine holding the current-carrying straight conductor in your right hand such that the thumb points in the direct...

Question 8

Q8: When does an electric short circuit occur?

Accepted Answer

An electric short circuit occurs when the live wire and the neutral wire in an electric circuit come into direct contact with each other. This can happen due to factors like: - The insulation of the wires getting damaged or wearing out over time. - A fault or defect within an electrical appliance. W...

Question 9

Q9: What is the function of an earth wire? Why is it necessary to earth metallic appliances?

Accepted Answer

Function of an earth wire: The primary function of an earth wire is to act as a safety measure, protecting users from severe electric shocks. It provides a low-resistance path for any leakage current to flow directly into the earth. Necessity of earthing metallic appliances: It is necessary to earth...

NCERT Solutions