Current Electricity — Physics STD 12 Science — Question

A brass plate having surface area 200cm² on one side is electroplated with 0·10mm thick silver layers on both sides using a 15A current. Find the time taken to do the job. The specific gravity of silver is 10.5 and its atomic weight is 107.9 g/mol.

Figure. shows two positions of a loop PQR in a perpendicular uniform magnetic field. In which position of the coil is there an induced emf?

Explain some of the far reaching consequences of displacement current.

A parallel plate capacitor made of circular plates each of radius R = 6.0 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V ac supply with a (angular) frequency of 300 rad s_^-1.

1. What is the rms value of the conduction current?
2. Is the conduction current equal to the displacement current?
3. Determine the amplitude of B at a point 3.0 cm from the axis between the plates.

A gas of hydrogen-like ions is prepared in a particular excited state A. It emits photons having wavelength equal to the wavelength of the first line of the Lyman series together with photons of five other wavelengths. Identify the gas and find the principal quantum number of the state A.

A power transmission line feeds input power at 2300V to a stepdown transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?

The outer surface of a cylinder containing a gas is rubbed vigorously by a polishing machine. The cylinder and its gas become warm. Is the energy transferred to the gas heat or work?

Write the definition of concave mirror and convex mirror.

1. Identify the logic gates marked P and Q in the given logic circuit.

2. Write down the output at X for the inputs A = 0, B = 0 and A = 1, B = 1.

Explain J J. Thomson's plum pudding model of atom.