# BASIC ELECTRONICS Test 14 Paper: Physics      Class: 10                    Time Allowed:    One Hour                           Marks: 25 Q1. Circle the correct answer.  (10)

1.If we increase the number of loops,the turning effect:
a) increase slightly                  b) increase greatly            c) decrease suddenly               d) remains same
2.In a practical electric motor, the coil is called:
a) armature                b) coil                 c) electromagnet               d) all of these
3.Which rule is used to find direction of the force on a current carrying wire in a magnetic field?
a) right hand rule             b) Fleming’s left hand rule               c) head to tail rule             d) Hero’s formula
4.The lines of force of a coil are directed……………to its plane.
a) parallel              b) anti parallel                   c) perpendicular                  d) inclinde
5.Which of the following have two coils, primary and secondary?
a) transformer                  b) ac generator                c) dc motor                  d) none of these
6.Who found the direction of induced e.m.f. first time?
a) lenz             b) henry             c) newton            d) bohar
7.The phenomenon of production of induced current in one coil due to change of current in a neighbouring coil is called:
a) electromagnetic induction              b) electrostatic induction               c) mutual induction               d) self induction
8.The direction of magnetic lines of force can be determined by:
a) left hand rule             b) right hand rule             c) head to tail rule             d) None of these
9.Which statement is true about the magnetic poles?
a) unlike pole repel                        b) like pole attract                                                                                                                       c) magnetic poles do not effect each other                 d) a single magnetic pole does not exist
10.Transfer is used to change the value of:
a) Voltage              b) power              c) Energy               d) Potential

Q2. Write short answers to these questions: (15)
1.What is relay? How it works?
2.State Fleming’s left hand rule.
3.What is the function of split Rings in the D.c motor.
4.What is a electromagnet?
5.What is transformer?