Physics

An EM wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure p on it. Which of the following are true?

(a) Radiation pressure is I/c if the wave is totally absorbed

(b) Radiation pressure is —I/c if the wave is totally reflected

(c) Radiation pressure is 2I/c if the wave is totally reflected

(d) Radiation pressure is in the range I/c < p < 2I/c for real surfaces

Relativistic corrections become necessary when the expression for the kinetic energy 1/2 mv², becomes comparable with mc². where m is the mass of the
At what de-Broglie wavelength, will relativistic corrections become important for an electron? 
(a) A=10nm (b) A =10^-1 nm (c) A=10^-4 nm (d) A=10^-6 nm

An electron mass m with initial velocity v=v₀i is an electric field E=E_o if $\lambda =\frac{h}{mv}=h/$ its debroglie wavelength at time t is given by

(a) ${\mathit{\lambda }}_{\mathit{o}}$

(b) ${\mathit{\lambda }}_{\mathit{o}}\sqrt[]{1+\frac{{\mathit{e}}^2{\mathit{E}}_{\mathit{o}}^2{\mathit{t}}^2}{{\mathit{m}}^2{\mathit{v}}_{\mathit{o}}^2}}$

(c) ${\mathit{\lambda }}_{\mathit{o}}/\mathit{}\sqrt[]{1+\frac{{\mathit{e}}^2{\mathit{E}}_{\mathit{o}}^2{\mathit{t}}^2}{{\mathit{m}}^2{\mathit{v}}_{\mathit{o}}^2}}$

(d) ${\mathit{\lambda }}_{\mathit{o}}/\mathit{}\sqrt[]{1+\frac{{\mathit{e}}^2{\mathit{E}}_{\mathit{o}}^2{\mathit{t}}^2}{{\mathit{m}}^2{\mathit{v}}_{\mathit{o}}^2}}$

The source of electromagnetic waves can be a charge

(a) Moving with a constant velocity

(b) Moving in a circular orbit

(c) At rest

(d) Falling in an electric field

A charged particle oscillates about its mean equilibrium position with a frequency of 10⁹ The electromagnetic waves produced

(a) Will have frequency of 10⁹Hz

(b) Will have frequency of 2 x 10⁹ Hz

(c) Will have wavelength of 0.3 m

(d) Fall in the region of radio waves

An electron mass m with an initial velocity v=v_oi is in an electric field E=-E_oi. its debroglie wavelength at time t is given by $\mathrm{T}\mathrm{y}\mathrm{p}\mathrm{e}\mathrm{}\mathrm{e}\mathrm{q}\mathrm{u}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{}\mathrm{h}\mathrm{e}\mathrm{r}\mathrm{e}.$

(a) $\frac{{\mathit{\lambda }}_{\mathit{o}}}{1+\frac{\mathit{e}{\mathit{E}}_{\mathit{o}}}{\mathit{m}}\frac{\mathit{t}}{{\mathit{v}}_{\mathit{o}}}}$

(b) ${\mathit{\lambda }}_{\mathit{o}}\left(1+\frac{\mathit{e}{\mathit{E}}_{\mathit{o}}\mathit{t}}{\mathit{m}{\mathit{v}}_{\mathit{o}}}\right)$

(c) ${\mathit{\lambda }}_{\mathit{o}}$

(d) ${\mathit{\lambda }}_{\mathit{o}}\mathit{t}$

A plane electromagnetic wave propagating along x-direction can have the following pairs of E and B.

(a) E_x, B_y       

(b) E_y, B_z

(c) B_x,E_y       

(d) E_z,B_y

An electromagnetic wave travelling along z-axis is given as E=E₀cos(kz-wt).choose the correct options from the following

(a) Tha associated magnetic field is given as B=1/ck $*$ E=1/w(k $*\mathit{E}$ )

(b) The electromagnetic field can be written in terms of associated magnetic field as E=c(b $*\mathit{k}$ )

(c) E=0,k.B=0

(d) K $*$ E=0,k $*\mathit{B}=0$

An electron is moving with an initial velocity v = v₀i and is in a magnetic field B = B₀ Then, its de-Broglie wavelength
(a) Remains constant
(b) Increases with time
(c) Decreases with time
(d) Increases and decreases periodically

An electromagnetic wave travels in vacuum along z-direction E=  (E₁iE₂j)cos(kz-wt). Choose the correct options from the following

(a) The associated magnetic field is given as B= (E₁i-E₂j)cos(kz-wt)

(b) The associated magnetic field is given as B= (E₁i-E₂j)cos(kz-wt)

(c) The given electro magnetic field is circularly polarised

(d) The given electromagnetic wave is plane polarised