1
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
The condition under which a microwave oven heats up a food item containing water molecules most efficiently is
A
Microwaves are heat waves, so always produce heating.
B
Infra-red waves produce heating in a microwave oven.
C
The frequency of the microwaves must match the resonant frequency of the water molecules.
D
The frequency of the microwaves has no relation with natural frequency of water molecules.
2
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced e.m.f. is
A
four times per revoluation
B
six times per revolution
C
once per revolution
D
twice per revolution
3
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when
A
a capacitance of reactance XC = XL is included in the same citcuit.
B
an iron rod is inserted in the coil.
C
frequency of the AC source is decreased.
D
number of turns in the coil is reduced.
4
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
The wavelength $$\lambda $$e of an electron and $$\lambda $$p of a photon of same energy E are related by
A
$${\lambda _p} \propto \sqrt {{\lambda _e}} $$
B
$${\lambda _p} \propto {1 \over {\sqrt {{\lambda _e}} }}$$
C
$${\lambda _p} \propto {\lambda _e}^2$$
D
$${\lambda _p} \propto {\lambda _e}$$