Dual Nature of ...

In order to coincide the parabolas formed by singly ionised ions in one spectrograph and doubly ionized ions in the other Thomson\'s mass spectrograph, the electric fields and magnetic fields are kept in the ratios 1 : 2 and 3 : 2 respectively. Then the ratio of masses of the ions is

Let λ_α, λ_β and λ’_α, denote the wavelengths of the X-rays of the K_α, K_β and L_α lines in the characteristic X-rays for a metal. Then

The minimum intensity of light to be detected by human eye is 10^–10 W/m². The number of photons of wavelength 5.6 × 10^–7 m entering the eye, with pupil area 10^–6 m², per second for vision will be nearly

In X-ray tube when the accelerating voltage V is halved, the difference between the wavelength of K_α line and minimum wavelength of continuous X-ray spectrum

In a photocell bichromatic light of wavelength 2475 Å and 6000 Å are incident on cathode whose work function is 4.8 eV. If a uniform magnetic field of 3 × 10^–5 tesla exists parallel to the plate, the radius of the path described by the photoelectron will be (mass of electron = 9 × 10^–31 kg)

Two metallic plates A and B, each of area 5 × 10^–4m² are placed parallel to each other at a separation of 1 cm. Plate B carries a positive charge of 33.7 pc. A monochromatic beam of light, with photons of energy 5 eV each, starts falling on plate A at t = 0, so that 10¹⁶ photons fall on it per square meter per second. Assume that one photoelectron is emitted for every 10⁶ incident photons. Also assume that all the emitted photoelectrons are collected by plate B and the work function of plate A remains constant at the value 2 eV. Electric field between the plates at the end of 10 seconds is

In the following arrangement y = 1.0 mm, d = 0.24 mm and D = 1.2 m. The work function of the material of the emitter is 2.2 eV. The stopping potential V needed to stop the photo current will be

The eye can detect 5 × 10⁴ photons per square metre per sec of green light (λ = 5000 Å) while the ear can detect 10^–13 (W/m²). The factor by which the eye is more sensitive as a power detector than the ear is close to

A photon collides with a stationary hydrogen atom in ground state inelastically. Energy of the colliding photon is 10.2 eV. After a time interval of the order of micro second another photon collides with same hydrogen atom inelastically with an energy of 15 eV. What will be observed by the detector?

The curve drawn between velocity and frequency of photon in vacuum will be a