Class 12th

Why doesn't Gauss Law hold true for calculating electric field for every charge distribution?

Will Gauss' Law still apply if the Gaussian surface passes through a charge?

Variation of photoelectric current with intensity of light for a given frequency, is

In Young double slit experiment the n^th red bright band coincide with (n + 1)^th blue bright band. If the wavelength of red and blue light are 7500 Å and 5000 Å, then the value of 'n' is

The pressure exerted by an electromagnetic wave of intensity I(W/M²) on a non-reflecting surface is (c is the velocity of light)

A potentiometer wire of length 100 cm has resistance of 20 ohm. It is connected in series with an external resistance and a cell of emf 2 volt and of negligible internal resistance. A source of emf 20 mV is balance against a length of 40 cm of the potentiometer wire. What is the value of external resistance?

A fish from inside water sees a bird in air at a distance

Four metallic plates, each with a surface area A, are placed at a distance d from each other as shown in the figure. If points A and B is connected with a battery of emf V, then the charge on the plate a will be   

Activity of radioactive element decrease to one-fourth of original activity R₀ in 16 years, after further 16 years, its activity will be  

The distance of closest approach of an alpha particle fired towards gold nucleus with kinetic energy k is r₀. The distance of closest approach when the alpha particle is fired towards same nucleus with kinetic energy 4k will be