1
NEET 2016 Phase 2
+4
-1
Electrons of mass m with de-Broglie wavelength $$\lambda$$ fall on the target in an X-ray tube. The cutoff wavelength ($$\lambda$$0) of the emitted X-ray is
A
$$\lambda$$0 = $${{2mc{\lambda ^2}} \over h}$$
B
$${\lambda _0} = {{2h} \over {mc}}$$
C
$${\lambda _0} = {{2{m^2}{c^2}{\lambda ^3}} \over {{h^2}}}$$
D
$${\lambda _0} = \lambda$$
2
NEET 2016 Phase 2
+4
-1
Photons with energy 5 eV are incifent on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is
A
+ 3 V
B
+4 V
C
$$-$$1 V
D
$$-$$3 V
3
NEET 2016 Phase 1
+4
-1
When a metallic surface is illuminated with radiation of wavelength $$\lambda$$, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2 $$\lambda$$, the stopping potential is $${V \over 4}$$. The threshold wavelength for the metallic surface is
A
$${5 \over 2}\lambda$$
B
3$$\lambda$$
C
4$$\lambda$$
D
5$$\lambda$$
4
NEET 2016 Phase 1
+4
-1
An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is
A
$$c{\left( {2mE} \right)^{{1 \over 2}}}$$
B
$${1 \over c}{\left( {{{2m} \over E}} \right)^{{1 \over 2}}}$$
C
$${1 \over c}{\left( {{E \over {2m}}} \right)^{{1 \over 2}}}$$
D
$${\left( {{E \over {2m}}} \right)^{{1 \over 2}}}$$
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