Class 12th

The wavelength of an X-ray beam is $10\stackrel{o}{A}.$ The mass of a fictitious particle having the same energy as that of the X-ray photons is $\frac{x}{3}hkg.$ The value of x is………. (h = Planck's constant)

A current of 6 A enters one corner P of an equilateral triangle PQR having 3 wires of resistance $2\Omega$  each and leaves by the corner R. The currents i₁ in ampere is………

Two small spheres each of mass 10mg are suspended from a point by threads 0.5m long. They are equally charged and repel each other to a distance of 0.20m. The charge on each of the sphere is $\frac{a}{21}*10^{-8}C.$  The value of 'a' will be……. [Given g = 10 ms^-2]

An electron with kinetic energy K₁ enters between parallel plates of a capacitor at an angle 'α' with the plates. It leaves the plates at angle 'β' with kinetic energy K₂. Then the ratio of kinetic energies K₁ : K₂ will be

In a ferromagnetic region with zero magnetization.

The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n = 2 to n = 1 state is

An electron of mass m_e and a proton of mass m_p = 1836 m_e are moving with the same speed. The ratio of their de Broglie wavelength $\frac{{\lambda }_{electron}}{{\lambda }_{proton}}$  will be

Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter $0.1\mu m.$  If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that

If a message signal of frequency 'f_m' is amplitude modulated with a carrier signal of frequency 'f_c' and radiated through an antenna, the wavelength of the corresponding signal in air is