1
AIPMT 2012 Prelims
MCQ (Single Correct Answer)
+4
-1
Change Language
The electric field associated with an em wave in vacuum is given by
E = $$\widehat i$$ 40 cos (kz $$-$$ 6 $$ \times $$ 108 t) where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is
A
2 m$$-$$1
B
0.5 m$$-$$1
C
6 m$$-$$1
D
3 m$$-$$1
2
AIPMT 2012 Prelims
MCQ (Single Correct Answer)
+4
-1
Change Language
A 200 W sodium street lamp emits yellow light of wavelength 0.6 $$\mu $$m. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
A
1.5 $$ \times $$ 1020
B
6 $$ \times $$ 1018
C
62 $$ \times $$ 1020
D
3 $$ \times $$ 1019
3
AIPMT 2012 Prelims
MCQ (Single Correct Answer)
+4
-1
Change Language
An $$\alpha $$-particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 Wb/m2. The de Broglie wavelength associated with the particle will be
A
1 $$\mathop A\limits^ \circ $$
B
0.1 $$\mathop A\limits^ \circ $$
C
10 $$\mathop A\limits^ \circ $$
D
0.01 $$\mathop A\limits^ \circ $$
4
AIPMT 2012 Prelims
MCQ (Single Correct Answer)
+4
-1
Change Language
Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the material is
A
4 $$ \times $$ 1015 Hz
B
5 $$ \times $$ 1015 Hz
C
1.6 $$ \times $$ 1015 Hz
D
2.5 $$ \times $$ 1015 Hz