NEET Physics Electromagnetic Waves Questions Solved

In an electromagnetic wave in free space the root mean square value of the electric field is $E_{rms}=6$ V/m. The peak value of the magnetic field is 

(a) 1.41$\times {10}^{-8}T$

(b) $2.83\times {10}^{-8}T$

(c) $0.70\times {10}^{-8}T$

(d) $4.23\times {10}^{-8} T$

Out of the following options which one can be used to produce a propagating electromagnetic wave?

(a) A stationary charge               (b) A chargeless particle

(c) An accelerating charge          (d) A charge moving at constant velocity

The energy of the EM wave is of the order of 15 KeV. To which part of the spectrum does it belong?

(a)X-rays

(b)Infrared rays

(c)Ultraviolet rays

(d)$\gamma$-rays

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

(a) the frequency of the microwave must match the resonant frequency of the water molecules

(b) the frequency of the microwave  has no relation with natural frequency of water molecules

(c) microwave are heat waves, so always produce heating

(d) infrared waves produce heating in a microwave oven
 

The electric field associated with an electro magnetic wave in vacuum is given by E= 40cos$\left(kz-6\times {10}^{8}t\right),$where E,z and t are in volt/m, metre and second respectively.The value of wave vector k is 

(a) $2 m^{-1}$                               (b) $0.5 m^{-1}$

(c) $6 m^{-1}$                               (d) 3 $m^{-1}$             

The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum 

is equal to

(a) the speed of light in vacuum

(b) reciprocal of speed of light in vacuum

(c) the ratio of magnetic permeability to the

electric susceptibility of vacuum

(d) unity