Chapter-15: Electromagnetism

 

Here this post contains Short Question and Answers of Chapter 15 - Physics for 10th Class "Electromagnetism". Learn these question answers and other related stuff for exam preparation.

In Chapter-15 Electromagnetism is the study of magnetic effects of current. The uses of electromagnetism in different fields of science and technology is very wide. 

• Motors and electric meters are based on the effect of magnetism produced by the electric current in wires. 
• Generators produce electric current due to the movement of wires near very large magnets. 

Short Question Answer
Q-1:	Define resistance.
Ans:	Magnetic field lines help us to visualize the magnitude and direction of the magnet.
Q-2:	What is the field coil?
Ans:	To produce magnetic field, we use permanent magnet or electromagnet which is called field coil.
Q-3:	State Lenz's law?
Ans:	The direction of an induced current in a circuit is always such that it opposes the cause that produces it is called lenz’s law.
Q-4:	Define mutual induction?
Ans:	The phenomenon of production of induced current in one coil due to change of current in a neighboring coil is called mutual induction.
Q-5:	Define electromagnetic induction?
Ans:	The process of generating an induced current in a circuit by changing the number of magnetic lines of force passing through it is called electromagnetic induction.
Q-6:	Define Right hand rules.
Ans:	“grasp a wire with your right hand such that your thumb pointed in the direction of conventional current. Then curling fingers of the hand will point out the direction of magnetic field”
Q-7:	Define magnetic field strength.
Ans:	The number of magnetic lines of forces passing through a surface area is called magnetic field strength.
Q-8:	What is the solenoid?
Ans:	A long coil of wire consisting of many loops is called solenoid.
Q-9:	What electromagnet?
Ans:	The type of temporary magnet, which is created when current flows through a coil, is called electromagnet.
Q-10:	What is electromagnetism? What are its uses?
Ans:	Electromagnetism is the study of magnetic effect of current. Use: 1. Motors and electric meters are based on the effects of magnetism produced by electric current in wires. 2. Generator produce electric current due to the movement of wires near very large magnets.
Q-11:	Difference between generator and a motor?
Ans:	Generator: 1. In generator, we move the coil and current is produced. 2. It converts mechanical energy into electrical energy.
Q-12:	Can a transformer operate on direct current?
Ans:	Transformer is used to increase or decrease the A.C. voltage, therefore a transformer cannot be operated on D.C. current.
Q-13:	What is Faraday's law of electromagnetic induction?
Ans:	The value of induced e.m.f in a circuit is directly proportional to the rate of change of number of magnetic lines of force passing through it.
Q-14:	Which device is used for converting electrical energy into mechanical energy?
Ans:	Electric motor is a device which is used to convert electrical energy into mechanical energy.
Q-15:	Explain application of electromagnet with the help of relay?
Ans:	Relay: A relay is an electrical switch that opens and closes under the control of electrical circuit. FUNCTION: The relay is used to control a large current with the help of small current.
Q-16:	Define primary coil.
Ans:	The coil in which change in current induces current in neighboring coil is called primary coil.
Q-17:	What is the basis of MRI technique?
Ans:	Weak ionic current in our body that travels along the nerve can produce the magnetic effect. This forms the basis of obtaining images of different parts of body. This is done using the technique called magnetic
Q-18:	What is the principle of walk-through metal detectors?
Ans:	Walk through metal detectors are installed at air ports and other places for security purpose. These detectors detect metal weapons etc. Using the principle of electromagnetic induction.
Q-19:	Define magnetic flux.
Ans:	The number of magnetic lines of force passing through any surface is known as magnetic flux.
Q-20:	On which principle generator works in hydroelectric dam?
Ans:	A generator inside hydroelectric dam uses electromagnetic induction to convert mechanical energy of spinning turbines into electrical energy.