Electromagnetism

This is the correct answer. The function of a commutator ring is to reverse the direction of current flowing.

This is the correct answer. Since the current is induced in the wire by moving it in a magnetic field, so it is called induced current.

This is the correct answer. Galvanometer is used for detecting current in an electric generator.

This is the correct answer. Polarity of an electromagnet can be changed by changing the direction of current.

This is the correct answer. When a rectangular copper coil is rotated in a magnetic field, the direction of the induced current changes every half revolution, due to which, the current in the coil remains the same.

This is the correct answer. Household circuits are connected in parallel because if there is any problem in the circuit, it will not affect the rest of the circuit. Fuses are connected in series because as soon as the current in the circuit exceeds the maximum value, the fuse wire will melt and prevent fire.

This is the correct answer. Electric generator works on Fleming's right-hand rule. Electric dynamo is an electric generator widely used in power stations for producing electric current.

This is the correct answer. Alternating current changes its direction in every 1/100 s.

This is the correct answer. This prevents overloading in circuit because current drawn is equal to the maximum capacity of the components.

This is the correct answer. When a straight conductor is moved in a magnetic field, current is induced in the circuit.

This is the correct answer. Current drawn by the electric oven, I = P/V = 2000/220 = 9 A. The current exceeds the safe limit of the circuit and hence, the fuse will melt.

This is the correct answer. Magnetic field around a current-carrying straight wire is concentric in nature whose centre is the wire.

This is the correct answer. Magnetic field produced in a long straight solenoid carrying current is uniform at all the points.

This is the correct answer. The strength of the magnetic field is the greatest at the centre as all lines of force add up to each other.

This is the correct answer. An MRI (or magnetic resonance imaging) scan is a radiology technique that uses magnetism, radio waves, and a computer to produce images of body structures.

This is the correct answer. The magnetic field produced in a bar magnet is similar to a solenoid.

This is the correct answer. According to Fleming's left hand rule: Hold out your left hand with forefinger, middle finger and thumb at right angle to one another. If the fore finger represents the direction of the field and the middle finger represents the direction of the current, then thumb gives the direction of the force. In this case, the direction of the charge particle is towards east, i.e. the direction of the current repesented by the fore finger and the thumb repesents the direction of the force. The fore finger represents the direction of the magnetic field.

This is the correct answer. When there is no movement in either the magnet or the coil, there will be no induced current in the circuit and hence no deflection.