Question
Explain the concept of energy bands with a figure.
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With the help of a labelled diagram, explain how does an AC works. There are $N$ turns in coil of AC generator. Area of each turn is A and the coil is rotating with a uniform angular velocity. Establish an expression for generated induced electromotive force. What is the source of energy production by this method?
→An ammeter is to be constructed that can read currents up to 2.0A. If the coil has resistance of $25\Omega$ and takes 1mA for full-scale deflection, what should be the resistance of the shunt used?
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All the surfaces shown in are frictionless. The mass of the car is M, that of the block is m and the spring has spring constant k. Initially, the car and the block are at rest and the spring is stretched through a length x, when the system is released.
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Figure shows two identical parallel plate capacitors connected to a battery through a switch S. Initially, the switch is closed so that the capacitors are completely charged. The switch is now opened and the free space between the plates of the capacitors is filled with a dielectric of dielectric constant 3. Find the ratio of the initial total energy stored in the capacitors to the final total energy stored.
A wire of length l is bent in the form of an equilateral triangle and carries an electric currrent i.
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Find the time period of small oscillations of the following systems.
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- A uniform square plate of edge a suspended through a corner.
- A unifrom disc of mass m and radius r suspended through a point $\frac{\text{r}}{2}$ away from the centre.
A current i is passed through a silver strip of width d and area of cross-section A. The number of free electrons per unit volume is n.
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Two circular coils of radii 5.0cm and 10cm carry equal currents of 21 A. The coils have 50 and 100 turns reepectively and are placed in such a way that their planes as well as the centres coincide. Find the magnitude of the magnetic field B at the common centre of the coils if the currents in the coils are (a) in the same sense (b) in the opposite sense.
A parallel beam of white light is incident normally on a water film 1.0 × 10-4cm thick. Find the wavelength in the visible range (400nm - 700nm) which are strongly transmitted by the film. Refractive index of water = 1.33.