Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

What effect does the dielectric medium have on the capacitance of a capacitor?

When a body is weighed on an ordinary balance we demand that the arm should be horizontal if the weights on the two pans are equal. Suppose equal weights are put on the two pans, the arm is kept at an angle with the horizontal and released. Is the torque of the two weights about the middle point (point of support) zero? Is the total torque zero? If so, why does the arm rotate and finally become horizontal?

What is the reason that the numbers of absorption transitions is less than the emission transition in atom?

Show graphically, the variation of the de-Broglie wavelength (λ) with the potential (V) through which an electron is accelerated from rest.

An incomplete sentence about transistors is given below:
The emitter ...... junction is ....... and the collector ..... junction is ..... The appropriate words for the dotted empty positions are, respectively.

1. 'Collector' and 'base'.
2. 'Base' and 'emitter'.
3. 'Collector' and 'emitter'.
4. 'Base' and 'base'.

A hollow metal sphere and a solid metal sphere of equal radii are given equal charges. Which of the two will have higher potential?

Which electromagnetic waves are produced by the Hertz experiment and what is the range of their wavelength?

In a circuit containing a capacitor and an AC source the current is zero at the. stant the source voltage is maximum. Is it consistent with Ohm's law?

At a place, the horizontal component of earth's magnetic field is B and angle of dip is 60°. What is the value of horizontal component of the earth's magnetic field at equator?

A resistance R is connected across a cell of emf ε and internal resistance r. A potentiometer now measures the potential difference between the terminals of the cell as V. Write the expression for 'r' in terms of ε, V and R.