# BASIC ELECTRONICS Test 13

Paper: Physics      Class: 10                    Time Allowed:    One Hour                           Marks: 25

Q1. Circle the correct answer.  (10)

1.Who found the direction of induced e.m.f. first time?
a) lenz                b) henry               c) newton            d) bohar
2.Transfer is used to change the value of:
a) Voltage           b) power             c) Energy               d) Potential
3.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
4.The lines of force of a coil are directed……………to its plane.
a) parallel             b) anti parallel                 c) perpendicular               d) inclinde
5.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
6.Which statement is true about the magnetic poles?
a) unlike pole repel                b) like pole attract                                                                                                                               c) magnetic poles do noteffect each other                    d) a single magnetic pole does not exist
7.Which of the following have two coils, primary and secondary?
a) transformer           b) ac generator              c) dc motor              d) none of these
8.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
9.In a practical electric motor, the coil is called:
a) armature             b) coil               c) electromagnet              d) all of these
10.If we increase the number of loops,the turning effect:
a) increase slightly            b) increase greatly           c) decrease suddenly               d) remains same

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