Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

An electrical cable of copper has just one wire of radius 9mm. Its resistance is 5 ohm. This single copper wire of the cable is replaced by 6 different well insulated copper wires each of radius 3mm. The total resistance of the cable will now be equal to:

Which of the following is not a point of similarity between Biot-Savart law and Coulomb’s law.

Chadwick was awarded the Nobel Prize in Physics in 1935 for his discovery of:

The molar heat capacity of oxygen gas at STP is nearly 2.5R. As the temperature is increased, it gradually increases and approaches 3.5R. The most appropriate reason for this behaviour is that at high temperatures:

1. Oxygen does not behave as an ideal gas.
2. Oxygen molecules dissociate in atoms.
3. The molecules collide more frequently.
4. Molecular vibrations gradually become effective.

In a semiconductor, the forbidden energy gap between the valence band and the conduction band is of the order is:

The third line of Balmer series of an ion equivalent to hydrogen atom has wavelength of 108.5 nm. The ground state energy of an electron of this ion will be(a) 3.4 eV(b) 13.6 eV(c) 54.4 eV(d) 122.4 eV

When a resistance of 2 ohm is connected across the terminals of a cell, the current is 0.5 A. When the resistance is increased to 5 ohm, the current is 0.25 A. The e.m.f. of the cell is(a) 1.0 V(b) 1.5 V(c) 2.0 V(d) 2.5 V

The resistance of Ammeter is :