7) IF the magnetic field is moving and the coil are both moving... will an emf b

Question

7) IF the magnetic field is moving and the coil are both moving... will an emf be present? a) Yes b) No c) Explain your answer 8) Faraday's Laws are important why? lo protect us fvom shock danger 9) The critical angle is important in which modern day application? 10) W hy does Snell's Law focus only deal with non-metallic surfaces? 11) A capacitor will store energy in its magnetic field a) True 6) False lec 12) In a solar panel, what is forced to move to produce a small emf? a) neutron b) photon c) electron d) proton e) hole 13) Where does the back emf come from? 14) In an inductor, it is said that the current leads the voltage by a phase of 90 a) True b) False c) They are the same

Explanation / Answer

7)

An emf is induced in a circuit when there is a relative motion between the moving magnetic field and the coil conductor . If both coil conductor and magnetic field is moving and there is arelative motion between them , then an EMF will be induced. If both magnetic field and coil conductor are moving in such a way that relative motion is between them is zero, then there will be no induced EMF.

Hence, for this question, EMF induce depend upon the direction of motion of the coil conductor and moving magnetic field.

9)

Fiber optics communication using optical fiber cable is an importnt modern day application of Critical angle. As optical communication depend upon total internal reflection through a material which depend on critical angle of the material used for optical fiber cable.

10)

Metals are generally opaque to a visible light and for higher frequency light absorption takes place in very thin outer layer, so  metallic films thinner than 0.1 m can transmit the light.

As we know Snell's law deal with the refration of light, which is very much possible to non-mettalic surfaces, as non-mettalic surfaces have ability to perform all four optical phenomena such as absorption, reflection, transmission and refraction. Therfore, Snell's law focuses only deal with non-mettalic surfaces.

11)

Since when voltage is applied across the capacitor positive and negative charge get separated to the plates of capacitor and this electric field is remain till the voltage source is removed. When the voltage source is removed, the charge particles tend to return to their original position and this cause a current to flow in the circuit. Hence, we can say that a capacitor stores energy in electric field.

12)

In a solar panel photon is forced towards the solar panel, which tends to energise the electrons of semiconducting material and elecltron move towrads n side and holes to the p-side of the p-n junction of the solar cell that leads to production of small emf.

Hence b) Photon is the answer

13)

When a EMF is produced in an inductive circuit due change in the magnetic flux , then the circuit has tendency to oppose the change of the flux, hence a current is induced to oppose the direction of change of magnetic flux and the self EMF produced by this Induced current in the curcuit and this induced self EMF is known as back EMF.

14)

b) false

In an inductive curcuit Voltage leads the current bythe phase of 90 degree (i.e. current lags the voltage by the phase of 90 degree)

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