In a plane electromagnetic wave, which of the following has/ have… - Vidyadip

MCQ

In a plane electromagnetic wave, which of the following has/ have zero average/value in one complete cycle?

$(a)$ Magnetic field

$(b)$ Magnetic energy

$(c)$ Electric field

$(d)$ Electric energy

✓
$(a), (c)$
B
$(b), (c)$
C
$(a), (d)$
D
All of these

✓

Answer

Correct option: A.

$(a), (c)$

a
(a)

Both $\vec{E}$ and $\vec{B}$ are sinusoidal, so over a complete cycle, its value will be zero.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 8. Electromagnetic waves→8. Electromagnetic waves — all question types→Physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

When an electron jumps from the fourth orbit to the second orbit, one gets the:

In the diagram a graph between the intensity of $X-$ rays emitted by a molybdenum target and the wavelength is shown, when electrons of $30\ keV$ are incident on the target. In the graph one peak is of ${K_\alpha }$ line and the other peak is of ${K_\beta }$ line

The distance of closest approach of an alpha particle is $d$ when it moves with a speed $V$ towards a nucleus.
Another alpha particle is projected with higher energy such that the new distance of the closest approach is $d/2.$ What is the speed of projection of the alpha particle in this case?

Two identical moving coil galvanometer have $10 \Omega$ resistance and full scale deflection at $2 \mu A$ current. One of them is converted into a voltmeter of $100 mV$ full scale reading and the other into an Ammeter of $1 mA$ full scale current using appropriate resistors. These are then used to measure the voltage and current in the Ohm's law experiment with $R =1000 \Omega$ resistor by using an ideal cell. Which of the following statement( $s$ ) is/are correct?

$(1)$ The measured value of $R$ will be $978 \Omega$

$(2)$ The resistance of the Voltmeter will be $100 k \Omega$.

$(3)$ The resistance of the Ammeter will be $0.02 \Omega$ (round off to $2^{\text {nd }}$ decimal place)

$(4)$ If the ideal cell is replaced by a cell having internal resistance of $5 \Omega$ then the measured value of $R$ will be more than $1000 \Omega$.

The laptop PC’s modern electronic watches and calculators use the following for display

Glass has refractive index m with respect to air and the critical angle for a ray of light going from glass to air is q. If a ray of light is incident from air on the glass with angle of incidence q, the corresponding angle of refraction is

A $NPN $ transistor conducts when

The input resistance of a silicon transistor is $100\,\,\Omega$. Base current is changed by $40\,\, \mu A$ which results in a change in collector current by $2\,\, mA.$ This transistor is used as a common emitter amplifier with a load resistance of $4\,\,k\Omega$. The voltage gain of the amplifier is

A wave can transmit ...... from one place to another

The horizontal component of earth's magnetic field at a certain place is $3 \times 10^{-5}\,T$ and direction of the field is from geographic south to geographic north. A very long straigh conductor is carrying steady current of $1\,A$ then calculate the force per unit length on it if the direction of current is from east to west (In $N/m$ )