1
AIEEE 2005
+4
-1
A photocell is illuminated by a small bright source placed $$1$$ $$m$$ away. When the same source of light is placed $${1 \over 2}$$ $$m$$ away, the number of electrons emitted by photo-cathode would
A
increases by a factor of $$4$$
B
decreases by a factor of $$4$$
C
increases by a factor of $$2$$
D
decreases by a factor of $$2$$
2
AIEEE 2004
+4
-1
The work function of a substance is $$4.0$$ $$eV.$$ The longest wavelength of light that can cause photo-electron emission from this substance is approximately.
A
$$310$$ $$nm$$
B
$$400$$ $$nm$$
C
$$540$$ $$nm$$
D
$$220$$ $$nm$$
3
AIEEE 2004
+4
-1
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal $$Vs$$ the frequency, of the incident radiation gives as straight the whose slope
A
depends both on the intensity of the radiation and the metal used
B
depends on the intensity of the radiation
C
depends on the nature of the metal used
D
is the same for the all metals and independent of the intensity of the radiation
4
AIEEE 2003
+4
-1
Two identical photo-cathodes receive light of frequencies $${f_1}$$ and $${f_2}$$. If the velocities of the photo electrons (of mass $$m$$ ) coming out are respectively $${v_1}$$ and $${v_2},$$ then
A
$$v_1^2 - v_2^2 = {{2h} \over m}\left( {{f_1} - {f_2}} \right)$$
B
$${v_1} + {v_2} = {\left[ {{{2h} \over m}\left( {{f_1} + {f_2}} \right)} \right]^{1/2}}$$
C
$$v_1^2 + v_2^2 = {{2h} \over m}\left( {{f_1} + {f_2}} \right)$$
D
$${v_1} - {v_2} = {\left[ {{{2h} \over m}\left( {{f_1} - {f_2}} \right)} \right]^{1/2}}$$
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