Electric generator MCQs
The device which converts mechanical energy in to electrical energy is called as Electric generator.
Principle of working: It works on principle of electromagnetic induction. Coil rotated in uniform magnetic field, induces current in it.
Armature coil: Number of turns of insulated copper wire wrapped on rectangular frame ABCD of soft iron forms armature. Ends of armature are connected to axle with brushes B1and B2 and split rings. The whole set up is suspended in two strong poles of U-shaped magnet. Sensitive galvanometer is connected to detect the direction of current.
Initially armature is in horizontal position, and then rotated in anticlockwise direction between two poles of horse-shoe magnet. Arm AC moves down, BD moves up this changes magnetic field on arms AC and BD of coil. Due to this current is induced in the arm AC and BD. By Fleming’s right hand rule the direction of current is from A to C and B to D through brush B1 and B2. After half rotation, arms AC and BD interchanges the position moves in opposite direction of previous and again current is induced in arms but now in opposite direction, this can be noticed in galvanometer.
Let’s learn the above article with the help of MCQs.
Q.1) Electromagnetic induction is the phenomenon in which…
a) changing magnetic field around coil induces current in it
b) changing current in the coil produces magnetic field in it
c) current flowing through coil produces heat in coil
d) all above are correct
Q.2) Who invented the phenomenon of Electromagnetic induction?
a) H. C. Christian b) J. C. Maxwell c) Michael Faraday d) Max Plank
Q.3) Which among the following rule/rules are used while studying the working of AC generator?
a) Flemings left hand rule b) Fleming’s right hand rule c) Right hand thumb
d) all of the above
Q.4) The current whose magnitude and direction reverses periodically is known as…
a) Steady current b) conventional current c) direct current d) alternating current
Q.5) Which among the following device is used for detecting the current along with its direction?
a) ammeter b) voltmeter c) galvanometer d) none of these
Q.6) Device which converts mechanical energy into electric energy is known as…
a) Electric generator b) Electric motor c) Electric geyser d) Fuse
Q.7)What should be direction of induced current in arms PQ and RS following figure
a) From P to Q in arm PQ and R to S in arm SR
b) From Q to P in arm PQ and S to R in arm SR
c) From Q to P in arm PQ and R to S in arm SR
d) From P to Q in arm PQ and S to R in arm SR
Q.8) An AC generator can be converted into DC generator by……….
a) removing commutator b) by adding commutator
c) by reducing turns of coil d) by reversing the magnetic field.
Q.9) Current in alternating generator is reversed with the help of ….
a) armature coil b) split rings c) brushes d) all of these
Q.10) The frequency of alternating current produced in India is around…
a) 50 Hz b) 100 Hz c) 5 Hz d) 10 Hz