How is an electromagnet made? Write any two ways by which the strength of electromagnet can be increased.
Magnetic field due to a current through a straight conductor
Usually 1 marks a paper · mostly MCQs and assertion-reason · asked in 3 of the last papers
Notes are being written
The board questions below are real and complete — they come from the CBSE papers themselves. The written notes for this topic are still being prepared.
Board questions on this topic
5 from the CBSE papers we hold — the exact wording the board used.
The pattern of the magnetic field produced inside a current carrying solenoid is: [four field-pattern diagrams labelled (a), (b), (c), (d) are given as the options]
The resultant magnetic field at point 'P' situated midway between two parallel wires (placed horizontally) each carrying a steady current I is
- (a) in the same direction as the current in the wires.
- (b) in the vertically upward direction.
- (c) zero.
- (d) in the vertically downward direction. [Diagram shows two horizontal wires, upper wire A->B and lower wire C->D both carrying current in the same direction, with point P midway between them.]
Assertion (A): The strength of the magnetic field produced at the centre of a current carrying circular coil increases on increasing the number of turns in it. Reason (R): The current in each circular turn has the same direction and the magnetic field due to each turn then just adds up. Options:
- (a) Both
- (b) and (R) are true and (R) is the correct explanation of (A).
- (c) Both
- (d) and (R) are true, but (R) is not the correct explanation of (A).
- (e) is true, but (R) is false.
- (f) is false, but (R) is true.
(i) What is a solenoid? (ii) Draw the pattern of magnetic field lines of the magnetic field produced by a solenoid through which a steady current flows.