K.C.S.E Physics Q & A - MODEL 1995PP2QN05

K.C.S.E Physics Q & A - MODEL 1995PP2QN05

(a) (i) State the law of electromagnetic induction
(ii) Describe an experiment to demonstrate Faraday's law 
(b) (i) A researcher studying the behaviour of step- up transformer made the following observations:
More joules per coulomb and fewer coulombs per second at the output than at the input terminals
Explain why the observation does not imply a violation of the principle of conservation of energy 
(ii) A transformer of 480 turns in the primary coil is used to connect a 9 volt a.c electric device to a 240 v.a.c mains power supply. Calculate the number of turns in the secondary coil. 

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ANSWERS

​. (a) (i) The magnitude of the induced e.m.f is directly proportional to the rate at which the conductor cuts the magnetic field lines
The induced current flows in such a direction as to oppose the changes producing it.
 
(ii) Plugging a magnetic into a coil

• in speed its g twins as straight of magnetic field
• Results in an increased in the induced e.m.f

(b) (i) Energy is neither created nor destroyed
            Make power constant
            VU = Joules    current = charge / time
                        Count                               
                        P = IV
            For large V, 1 must lower for power input to be equal to power output