Physics

(b, d) Here, in option (b) charge is moving in a circular orbit.

In circular motion, the direction of the motion of charge is changing continuously, thus it is an accelerated motion and this option is correct.

Also, we know that a charge starts accelerating when it falls in an electric field.

This is a multiple choice answer as classified in NCERT Exemplar

(a, c, d) as we know that  $\lambda =\frac{c}{\upsilon }$ = $\frac{3*{10}^8}{{10}^9}$  = 0.3m and it is fall in region of radio wave.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Answer- a

Explanation- $\lambda =\frac{h}{mv}$

Force F= -eE=-e [E_oi]=eE_oi

So a=f/m=eE_oi/m

V=V_oi+ eE_oit/m

$\lambda =\frac{h}{mv}$ h/ m V_oi+ eE_oit/m

This is a multiple choice answer as classified in NCERT Exemplar

(b, d) As electric and magnetic field vectors E and B are perpendicular to each other as well as Perpendicular to the direction of propagation of electromagnetic wave.

Here in the question electromagnetic wave is propagating along x-direction. So, electric and Magnetic field vectors should have either y-direction or z-direction.

This is a multiple choice answer as classified in NCERT Exemplar

(a, b, c) electromagnetic wave traveling along the z direction is given by

E=E₀cos (kz-wt)

The associated magnetic field B in electromagnetic wave is along xaxis along k $*E$

B₀=E₀/c=1/c (k $*E$ )

E=c (B $*k$ ) .As the angle is 90 so value is zero.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Answer- (a)

Explanation- v=v₀i and B =B₀j

Force on moving electron F= e (v $*B$ )

= e (v₀i $*B_0\mathrm{j}$ )=-eV₀B₀k

This is a multiple choice answer as classified in NCERT Exemplar

(d) as the electric and magnetic field in electromagnetic wave are perpendicular to each other also they are perpendicular to wave propagation so they are plane polarised.

This is a multiple choice answer as classified in NCERT Exemplar

(c) From a diode antenna, the electromagnetic waves are radiated outwards.The amplitude of electric field vector Eo which transports significant energy from the source falls off intensity inversely as the distance from the antenna, i.e. 1/r

This is a multiple choice answer as classified in NCERT Exemplar

(c) As from the relation that electric and magnetic energy density are equal to one another so there ratio will be always 1:1

This is a multiple choice answer as classified in NCERT Exemplar

(d) The direction of propagation of electromagnetic wave is perpendicular to both electric field vector E and magnetic field vector B, i.e., in the direction of E*B .

This can be seen by the diagram given below