1) An ultraviolet ray of energy 3.0ev falls on a metal surface and emmits electron....

1) An ultraviolet ray of energy 3.0ev falls on a metal surface and emmits electron. If the kinetic energy of the emitted electron is 1.15ev calculate the threshold frequency of the metal [1ev = 1.6 x 10⁻¹⁹J, h = 6.6 × 10⁻³⁴Js]
(a) 1.00 x 10¹⁵Hz
(b) 7.27 x 10¹⁴Hz
(c) 4.48 x 10¹⁴Hz
(d) 2.80 × 10¹⁴Hz
(e) 2.96 × 10⁻¹⁹Hz

2) The energy of an electron at the ground state is -1.25 × 10⁻¹⁹J. If the electron absorbed photon of wavelenght 2.5 × 10⁻⁶m to get to the next level, calculate the energy of the next level. [ c = 3.0× 10⁸m/s, h = 6.6 × 10⁻³⁴Js]
(a) -6.34 × 10⁻¹⁹J
(b) -2.04 × 10⁻²⁰J
(c) -2.04 × 10⁻¹⁹J
(d) 4.58 × 10⁻²⁰J
(e) 7.29 × 10⁻²⁰J?

1 Answers Available
Asked by Ronke on 22nd January, 2026