7. Calculate the velocity of ejected electron from the metal
surface when light of frequency 2 x 1015 Hz fall on the
metal surface and the threshold frequency is 7 x 1014 Hz
for metal ?
(a) 1.37 x 10^6
(b) 1.26 x 10^6
(C) 1.45 10^7
(d) 1.37 x 10^7
Answers
Answered by
0
Explanation:
v
o
=7.0×10
14
s
−1
v=1.0×10
15
s
−1
As we know, hv=hv
0
+
2
1
mv
2
i.e. h(v−v
0
)=K.E.
∴K.E.=(6.626×10
−34
)×(1.0×10
15
−7.0×10
14
)=6.626×10
−34
×10
14
(10−7)
∴K.E=19.878×10
−20
J
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