NEET 2013 (Karnataka) | Electromagnetic Waves Question 19 | Physics

An electromagnetic wave of frequency $$\upsilon = 3.0$$ MHz passes from vaccum into a dielectric medium with relative permittivity $${{\varepsilon _r}}$$ = 4.0. Then

Wavelength is doubled and frequency becomes half.

Wavelength is halved and frequency remains unchanged.

Wavelength and frequency both remain unchanged.

Wavelength is doubled and frequency unchanged.

NEET 2013

MCQ (Single Correct Answer)

-1

The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

Microwaves are heat waves, so always produce heating.

Infra-red waves produce heating in a microwave oven.

The frequency of the microwaves must match the resonant frequency of the water molecules.

The frequency of the microwaves has no relation with natural frequency of water molecules.

AIPMT 2012 Mains

MCQ (Single Correct Answer)

-1

The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagatting in vacuum is equal to

the speed of light in vacuum

reciprocal of speed of light in vacuum

the ratio of magnetic permeability to the electric susceptibility of vacuum

unity

AIPMT 2012 Prelims

MCQ (Single Correct Answer)

-1

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

2 m^$$-$$1

0.5 m^$$-$$1

6 m^$$-$$1

3 m^$$-$$1

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Biology

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Human Health and Diseases Body Fluids and Its Circulation Locomotion and Movement Neural Control and Coordination Reproduction in Organisms Reproductive Health Structural Organisation in Animals Digestion and Absorption Excretory Products and Their Elimination Chemical Coordination and Integration Human Reproduction Animal Kingdom Breathing and Exchange of Gases Evolution