When light of wavelength 248 nm falls on a metal of threshold energy 3.0 eV, the de-Broglie wavelength of emitted electrons is _______$$\mathop A\limits^o $$. (Round off to the Nearest Integer).

[ Use : $$\sqrt 3 $$ = 1.73, h = 6.63 $$\times$$ 10^$$-$$34 Js

m_e = 9.1 $$\times$$ 10^$$-$$31 kg; c = 3.0 $$\times$$ 10⁸ ms^$$-$$1; 1eV = 1.6 $$\times$$ 10^$$-$$19 J]

A ball weighing 10 g is moving with a velocity of 90 ms^$$-$$1. If the uncertainty in its velocity is 5%, then the uncertainty in its position is ___________ $$\times$$ 10^$$-$$33 m. (Rounded off to the nearest integer)

[Given : h = 6.63 $$\times$$ 10^$$-$$34 Js]

Electromagnetic radiation of wavelength 663 nm is just sufficient to ionise the atom of metal A. The ionization enegy of metal A in kJ mol^$$-$$1 is __________. (Rounded off to the nearest integer)

[h = 6.63 $$\times$$ 10^$$-$$34 Js, c = 3.00 $$\times$$ 10⁸ ms^$$-$$1, N_A = 6.02 $$\times$$ 10²³ mol^$$-$$1]

Among the following, number of metal/s which can be used as electrodes in the photoelectric cell is _________. (Integer answer)

(A) Li

(B) Na

(C) Rb

(D) Cs