Question 225 marksLong AnswerSection SECTION-A

(a) Draw magnetic field lines of a bar magnet. "Two magnetic field lines never intersect each other." Why?

(b) An electric oven of 1.5 kW1.5\text{ kW} is operated in a domestic circuit (220 V220\text{ V}) that has a current rating of 5 A5\text{ A}. What result do you expect in this case? Explain.

Figure for question 22
Magnetic Effects of Electric Current
Magnetic Field Lines

Official answer

(a) The magnetic field lines of a bar magnet are shown in the figure below. The magnetic field lines emerge from the north pole and enter the south pole. The magnetic field lines never intersect each other because if they did, it would mean that at the point of intersection, the compass needle would point towards two directions, which is not possible. (b) The electric oven of 1.5 kW is operated in a domestic circuit (220 V) that has a current rating of 5 A. The power consumed by the oven is given by P = VI, where V is the voltage and I is the current. Since the current rating of the circuit is 5 A, the maximum power that can be consumed by the oven is P = 220 x 5 = 1100 W. However, the oven consumes 1.5 kW = 1500 W, which is more than the maximum power that the circuit can supply. Therefore, we expect the circuit to trip or the oven to not function properly.

Answer keywords:magnetic field linesbar magnetelectric ovenpower consumption

Marking scheme

  1. 1.Magnetic field lines emerge from the north pole and enter the south pole.
  2. 2.Two magnetic field lines never intersect each other.
  3. 3.The electric oven consumes 1.5 kW of power, which is more than the maximum power that the circuit can supply.

Hint

Use the concept of magnetic field lines and their properties to answer part (a). Use the formula P = VI to calculate the maximum power that can be consumed by the oven in part (b).

Quick oral answer

The magnetic field lines of a bar magnet emerge from the north pole and enter the south pole. Two magnetic field lines never intersect each other because if they did, it would mean that at the point of intersection, the compass needle would point towards two directions, which is not possible. The electric oven consumes 1.5 kW of power, which is more than the maximum power that the circuit can supply. Therefore, we expect the circuit to trip or the oven to not function properly.

Common mistakes

  1. 1.Drawing magnetic field lines that intersect each other.
  2. 2.Not calculating the maximum power that can be consumed by the oven.
  3. 3.Not comparing the calculated power with the actual power consumed by the oven.

Analysis and explanation

The magnetic field lines of a bar magnet are used to visualize the magnetic field around the magnet. The magnetic field lines emerge from the north pole and enter the south pole. The magnetic field lines never intersect each other because if they did, it would mean that at the point of intersection, the compass needle would point towards two directions, which is not possible. The electric oven consumes 1.5 kW of power, which is more than the maximum power that the circuit can supply. Therefore, we expect the circuit to trip or the oven to not function properly.

Interesting facts

Magnetic field lines are used to visualize the magnetic field around a magnet.

The electric oven consumes a significant amount of power, which can cause the circuit to trip or the oven to not function properly.

Question details

Q22 of 36 questions

Board
CBSE
Class
Class 10
Subject
Science
Year
2014
Section
Section SECTION-A
Marks
5
Type
Long Answer
Chapter
Magnetic Effects of Electric Current
Topic
Magnetic Field Lines
Bloom's level
Understanding
Syllabus topic
Magnetic Field Lines

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Frequently asked questions

How many marks does this question carry in CBSE Class 10 Science 2014?

This question carries 5 marks in the CBSE Class 10 Science 2014 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Magnetic Effects of Electric Current" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Magnetic Field Lines" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2014 paper?

This is a Long Answer question from Section SECTION-A in the CBSE Class 10 Science 2014 paper.