RBSE Class 10 Science Chapter 12 Magnetic Effects of Electric Current

This post covers complete solutions of all intext and end exercise questions and let you secure the best results in RBSE and other board exams.

Chapter 12 Magnetic Effects of Electric Current

Answers of Questions on Page196

Q.1 Why does a compass needle get deflected when brought near a bar magnet?

Answer     

A compass needle is a small bar magnet and has North Pole and South Pole. When it is brought near a magnet same poles of bar magnet and needle repel each other and opposite poles attract each other and a compass needle gets deflection.

 

Answers of Questions on Page 200

Q.1 Draw magnetic field lines around a bar magnet.

Answer

Q.2 List the properties of magnetic lines of forces.

Answer     

(i). Magnetic field lines arises from the North pole and end in  the south pole of the bar magnet.

 (ii). These field line do not intersect each other at any point.

 (iii). Close magnetic line shows the stronger magnetic field and separated field lines show the weaker magnetic field.

 

Q.3 Why do two magnetic lines of force not intersect each other?

Answer  

Two magnetic lines of force do not intersect each other because at any point magnetic force acts in one direction.

 If they intersect, it means the magnetic field is in two directions which is not possible.

 

Answers of Questions on Page 201 & 202

Q.1 Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.

Answer   

Magnetic field will be downward to upward inside and upward to downward outside   perpendicular to any point on the loop.

Q.2 The magnetic field in given region is uniform. Draw a diagram to represent it.

Answer

Q3. The magnetic field inside a long straight solenoid-carrying current

  (a)  is zero.

  (b)  decrease as we move towards the end.

  (c)  increase as we move towards the end.

  (d)  is the same at all point.

Answer     (d)  is the same at all point.

Answers of Questions on Page 203 & 204

 

Q.1 Which of the following property of a proton can change while it moves freely in a magnetic field. [There maybe more than one correct answer]

 (a)  mass                   

 (b)  speed

 (c)  velocity             

 (d)  momentum

Answer   (c)  velocity       (d) momentum        

 

Q.2 In activity 3, how do we think the displacement of rod AB   will be affected if (i) current in rod AB is increased (ii) stronger horse-shoe magnet is used and (iii) length of the rod AB is increased.

Answer     

(i)   If current in rod AB is increased displacement of rod AB will be more.

(ii)  If, stronger horse-shoe magnet is used, displacement of rod AB will be increased.

(iii)         No effect in the displacement, if length of rod AB is increased.

 

Q.3 A positivity charged particle (alpha particle projected towards west is directed towards north by a magnetic field. The direction of magnetic field is     

 (a)  towards south          

 (b)  towards east

 (c)  downward       

  (d)  upward

Answer   (a)  towards south

Answers of Questions on Page 205

Q.1 Name two safety measures commonly used in electric circuits and appliances.

Answer   

Fuses and earth wires are used in electric circuits and appliances.

Q.2 An electric oven of 2 Kw   power is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.

Answer

 

Q.3 What precaution should be taken to avoid the overloading of domestic electric circuits?

Answer   

Electric fuses should be used in domestic circuits and appliances to prevent damage due to overloading.

 

Answers of End Exercise Questions

Q.1 Which of the following correctly describes the magnetic field near a long straight wire?

  (a) The field consists of straight lines perpendicular to the wire.

  (b)The field consists of straight lines parallel to the wire.

   (c) The field consists of radial lines originating from the wire.

   (d)The field consists of concentric circles centred on the wire.

Answer    

(d)  The field consists of concentric circles centred on the wire.

Q.2 At the time of short circuit, the current in the circuit.

  (a)  reduces substantially             

  (b)  does not change

  (c)  increase heavily            

  (d)  vary continuously

Answer     (c)  increase heavily

Q.3 State whether the following statements are true or false.

(a)  The field at the center of a ling circular coil carrying current will be parallel straight lines.

(b)  A wire with a green insulation is usually the live wire. 

Answer   (a) True            (b)  False

Q.4 List two method of producing magnetic field.

Answer      

(i)          Magnet  

(ii)  Current carrying conductor

Q.5 When is the force experienced by a current carrying conductor placed in a magnetic field is largest?

Answer   

According to the Fleming’s left l hand rule ,the force experienced by a current carrying conductor placed in a magnetic field is largest when the direction of current is at right angle to the direction of magnetic field.

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 deflected by a strong magnetic field to your right side. What is the direction of magnetic field?

Answer

Electrons are moving from back wall to the front, so the direction of current is towards you (the direction of current is taken opposite to the flow of electrons).

So applying the Fleming’s left hand rule, the direction of magnetic field inside the chamber is downward.

 

Q.7 State the rule to determine the direction of a (i) magnetic field produced around a straight conductor carrying current, (ii) force experienced by a current carrying straight conductor placed in a magnetic field which is perpendicular to it, and (iii) current induced in a coil due to its rotation in a magnetic field.

Answer      

(a)  Maxwell’s right hand rule.

(b)  Fleming’s left-hand rule.

 (c)  Fleming’s right hand rule.

 

Q.8 When does an electric short circuit occur?

Answer    

Short circuit occurs when the live wire comes directly in the contact of neutral wire due to damage of the insulation of wires or overloading.

Q.9 What is the function of an earth wire? Why is it necessary to earth metallic appliances?

Answer  

The earth wire endures that if there is any leakage of current to the metallic body of the appliance keeps its potential to that of the earth and the user may not get a severe electric shock and so earth wire is used as a safety wire.