Class 12th

In Young's double slit experiment, the wavelength of red light is 7800 Å and that of blue light is 5200 Å. minimum value of n for which n^th bright band due to red light coincides with (n + 1)^th bright band due to blue light, is:

Calculate the value of output voltage V₀ (in V) if the Si diode and  Ge diode conduct at 0.7V and 0.3V respectively as shown in figure.

An electron moving with a velocity of 2 m/s along +ve x-axis at a point in a magnetic field experiences a force of 2N along -ve y-axis. If the electron moves with of a velocity of 2 m/s along +ve y-axis at the same point, it experiences a force of 2N along +ve x-axis. Find force that the electron would experience if it were moving with a velocity of 2m/s along z-axis.

A proton and an $\alpha$ -particle both initially at rest are accelerated in a region of electric potential difference V and gravity free space. The proton is projected with gained kinetic energy against a uniform constant electric field and comes to momentary rest after travelling a distance $S_0$ . If the $\alpha$ -particle is also projected with gained kinetic energy against same electric field, it will come to momentary rest after travelling through:

Two infinite line charges having linear charge density λ₁ and λ₂ are placed along the x and y axis respectively. The electric field at a point (x₁, y₁) in the first quadrant is inclined at an angle of 60° with the x-axis. Then which of the following relations is correct.

Assuming the sun to be a spherical body (e = 1) of radius R at a temperature of T K, evaluate the total radiant power, incident on Earth having radius r₀, at a distance r from the Sun, where r₀ is the radius of the earth and $\sigma$  is Stefan's constant.

Magnetic field exists in the region between lines PQ and RS as shown in the figure. A particle having charge to mass ratio of a enters the magnetic field as shown in the figure with a speed v. Lines PQ and RS are parallel to each other. Find the value of d such that the charged particle exits the magnetic field region with velocity perpendicular to line RS.

Amount of radiation energy emitted by unit surface area per unit time by a body is defined as its emissive power. Dimension of Emissive power is:

In the circuit shown swith S is connected to position 2 for a long time and then joined to position 1. The total heat produced in resistance R₁ is:

At t  < 0, the capacitor is charged and the switch is opened. At t = 0 the switch is closed. The shortest time T at which the charge on the capacitor will be zero is given by: