1
NEET 2016 Phase 2
MCQ (Single Correct Answer)
+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
MCQ (Single Correct Answer)
+4
-1
If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength $$\lambda $$. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be
A
$${{16} \over {25}}\lambda $$
B
$${9 \over {16}}\lambda $$
C
$${{20} \over 7}\lambda $$
D
$${{20} \over {13}}\lambda $$
3
NEET 2016 Phase 2
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is
A
15
B
30
C
45
D
60
4
NEET 2016 Phase 2
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
For CE transistor amplifier, the aufio signal voltage across the collector resistance of 2 k$$\Omega $$ is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is 1 k$$\Omega $$, then the input signal voltage is
A
10 mV
B
20 mV
C
30 mV
D
15 mV
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