Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2026PhysicsChapterActual

Ultraviolet light of wavelength 310 nm is directed at three different metal plates P, Q, and R. The work functions of these metals are 2.2 eV , 3.5 eV , and 4.8 eV respectively. Which of the metal plates will emit photoelectrons? (Take hc = 1240 eV nm )

Options

  1. AP and Q only
  2. BR only
  3. CP only
  4. DQ and R only

Correct answer

A. P and Q only

Step-by-step solution

The energy of the incident photon is given by E = hc Substituting the given values: E = 1240 eV nm 310 nm = 4.0 eV For photoelectric emission to take place, the energy of the incident photon must be greater than the work function of the metal ( E > ). For metal P: 4.0 eV > 2.2 eV (Emission occurs) For metal Q: 4.0 eV > 3.5 eV (Emission occurs) For metal R: 4.0 eV Thus, photoelectrons will be emitted from plates P and Q only. Answer: P and Q only

Practice Chapter on Quantrex Academy →

More from Chapter

A solid spherical body of radius R , density , and specific heat capacity s is initially at temperature T₀ . It is placed in a vacuum chamber at absolute zero and cools by emitting 2026A straight canal has motorboats departing from two terminals at opposite ends. The motorboats depart at regular intervals of T minutes in both directions and travel at a constant s 2026A wooden crate is released from rest at the top of a ramp inclined at 37^ to the horizontal. When the ramp is perfectly smooth, the crate reaches the bottom with a speed v . When t 2026A uniform horizontal beam of mass 6 kg and length L is hinged to a vertical wall at one end. The other end is supported by a light inextensible wire attached to the same wall, maki 2026A bullet P of mass 30 g moving with a speed of 200 m/s penetrates a target and comes to rest after travelling a distance of 10 cm inside it. Another bullet Q of mass 20 g moving wi 2026A small block of mass m is placed at the highest point of a smooth fixed sphere of radius R . It is given a horizontal initial speed v₁ such that it slides down the surface. The bl 2026A block of mass 2 kg is projected with an initial speed of 14 m/s on a rough horizontal surface. The coefficient of kinetic friction between the block and the surface is 0.2 . Afte 2026A uniform horizontal circular disc of mass M and radius R is rotating freely about a vertical axis passing through its center at an angular speed of 40 rpm . Two small blocks, each 2026 Full Chapter list All NEET PYQs