Electric Charges and Fields — Physics STD 12 Science — Question

What do you mean by diffraction of light ?

When light travels from an optically denser medium to a rarer medium, why does the critical angle of incidence depend on the color of the light?

Calculate the shortest wavelength of the spectral lines emitted in Balmer series.

[Give Rydberg constant, R = 10⁷ m^-1]

Suppose you are told that the linear size of everything in the universe has been doubled overnight. Can you test this statement by measuring sizes with a metre stick? Can you test it by using the fact that the speed of light is a universal constant and has not changed? What will happen if all the clocks in the universe also start running at half the speed?

Three capacitors each of capacitance 9 pF are connected in series.

1. What is the total capacitance of the combination?
2. What is the potential difference across each capacitor if the combination is connected to a 120 V supply?

A gas thermometer measures the temperature from the variation of pressure of a sample of gas. If the pressure measured at the melting point of lead is 2.20 times the pressure measured at the triple point of water, find the melting point of lead.

The speed of a car as a function of time is shown in figure. Find the distance travelled by the car in 8 seconds and its acceleration.

In order to have a current in a long wire, it should be connected to a battery or some such device. Can we obtain the magnetic due to a straight, long wire by using Ampere's law without mentioning this other part of the circuit?

The angular magnification of a system is less than one. Does it mean that the image formed is inverted?

Can two identical and independent sodium lamps act as coherent sources? Give reason for your answer.