The work function of a metal is 4.2 eV. If radiations of 2000 mathringA fall on the metal, then the kinetic energy of the fastest photoelectron is:

Question

The work function of a metal is 4.2 eV. If radiations of 2000 mathringA fall on the metal, then the kinetic energy of the fastest photoelectron is: (A) 1.6 × 10-19 J (B) 16 × 1010 J (C) 3.2 × 10-19 J (D) 6.4 × 10-10 J

Tardigrade Admin · Accepted Answer

KE =( Energy of radiation - Work function ) =(h × (c/λ)-4.2) =((6.6 × 10-34 Js × 3 × 108 m /2000 × 10-10 m )) -(4.2 × 1.602 × 10-19 J ) =(9.9 × 10-19 J )-(6.7 × 10-19 J ) =3.2 × 10-19 J

Q. The work function of a metal is $4.2 e V$ . If radiations of $2000 \overset{˚}{A}$ fall on the metal, then the kinetic energy of the fastest photoelectron is:

$1.6 \times 1 0^{- 19} J$

$16 \times 1 0^{10} J$

$3.2 \times 1 0^{- 19} J$

$6.4 \times 1 0^{- 10} J$

Q. The work function of a metal is 4.2eV. If radiations of 2000A˚ fall on the metal, then the kinetic energy of the fastest photoelectron is:

1.6×10−19J

16×1010J

3.2×10−19J

6.4×10−10J

KE=( Energy of radiation − Work function ) =(h×λc​−4.2) =(2000×10−10m6.6×10−34Js×3×108m​) −(4.2×1.602×10−19J) =(9.9×10−19J)−(6.7×10−19J) =3.2×10−19J

Q. The work function of a metal is $4.2 e V$ . If radiations of $2000 \overset{˚}{A}$ fall on the metal, then the kinetic energy of the fastest photoelectron is:

$1.6 \times 1 0^{- 19} J$

$16 \times 1 0^{10} J$

$3.2 \times 1 0^{- 19} J$

$6.4 \times 1 0^{- 10} J$