C10 MAGNETIC EFFECT OF ELECTRIC CURRENT

1.     The magnetic effect of electric current was first discovered by:

• (a) Alexander Flemming                             

• (b) Oersted

• (c) Ampere                                                  

•  (d) Maxwell

2.     Which of the following correctly describes the magnetic field near a straight wire carrying current:

• (a) The field is uniform                           

• (b) The field is non-uniform

• (c) The field consists of concentric circles centered on the wire  

• (d) None of these

3.     The magnetic field inside a long straight solenoid carrying current is:

• (a)The same at all points                          

• b)Increases as we move towards its ends

• (c)Decreases as we move towards its ends         

• (d)Zero

4.     The direction of magnetic field lines due to a straight current carrying conductor B is given by:

• (a)Maxwell's right-handed screw rule          

• (b) Ohm's law

• (c)Coulomb's law                                               

• (d) None of these

5.     The adjoining figure represents the magnetic field caused by a current-carrying conductor which is:

• (a)A long straight wire        

• (b) A circular coil

• (c) A solenoid

• (d) A short straight wire                            

.    6.The intensity of magnetic field between the poles of an electromagnet would be unchanged, if:

•  (a)Current in the electromagnet coil is doubled

•  (b)Distance between the poles of electromagnet is halved

• (c) Direction of current in the electromagnet coil is reversed

• (d)Material of its core is changed.

7. The North-South polarities of an electromagnet can be determined easily by using:

• (a) Fleming’s right hand rule            

• (b)Clock face rule

•  (c) Right-hand screw rule                     

• (d) None of these

8. If the direction of current in a coil at its one face is anti-clockwise this end of coil will be:

                                        

• (a) South pole

•   (b) North pole

                                 

• (c)Both (a) and (b)

•   (d) None of these

 9. The direction of electric current in a solenoid when seen from a particular end is clockwise, then this end of the solenoid will be:

• (a) West pole

•   (b) South pole

• (c)North pole

• (d) East pole

 10. Which of the following substance is used to make an electromagnet:

 

• (a)  Aluminium

•  (b) Copper

• (c) Soft iron

•   (d) Steel