DUAL NATURE OF RADIATION AND MATTER — Physics STD 12 Science — Question

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?

A person is painting his house walls. He stands on a ladder with a bucket containing paint in one hand and a brush in other. Suddenly the bucket slips from his hand and falls down on the floor. If the bucket with the paint had a mass of 6.0kg and was at a height of 2.0m at the time it slipped, how much gravitational potential energy is lost together with the paint?

Write the formula for the force per unit length between two parallel current carrying wires. Using it, write the definition of Ampere and Coulomb.

Distinguish between polarised and unpolarized light. Does the intensity of polarised light emitted by a Polaroid depend on its orientation? Explain briefly.
The vibrations in a beam of polarised light make an angle of 60° with the axis of the polaroid sheet. What percentage of light is transmitted through the sheet?

Three circuits, each consisting of a switch ' S ' and two capacitors, are initially charged as shown in the figure. In which circuit, when the switch is closed, the charge on the given capacitor will (i) increase, (ii) decrease and (iii) remain unchanged? Give reason.

Find the position of the image formed by the lens combination given in the figure.

Why do semiconductors obey Ohm's law for only low fields?

Why is a white dress more comfortable than a dark dress in summer?