An observer is moving with half the speed of light towards a stat… - Vidyadip

MCQ

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency $10\ GHz$. What is the frequency of the microwave measured by the observer?.......$GHz$ ( speed of light $= 3 \times 10^8 $ $ms^{-1}$)

A
$10.1 $
B
$12.1 $
✓
$17.3$
D
$15.3$

✓

Answer

Correct option: C.

$17.3$

c
Use relativistic doppler's effect as velocity of observer is not small as compared to light

$f=f_{0} \sqrt{\frac{c+v}{c+v}}$ ; $V=$ relative speed of approach

$f_{0}=10\, \mathrm{GHz}$

$\therefore f=10 \sqrt{\frac{c+\frac{c}{2}}{c-\frac{c}{2}}}=10 \sqrt{3}=17.3\, \mathrm{GHz}$

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 10. Wave optics→10. Wave optics — all question types→Physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

Cells are joined in parallel. The internal resistance of the cell is:

In the circuti shown in the figure,$R = \sqrt {\frac{L}{C}} $ Switch $S$ is closed at time $t = 0$. The current through $C$ and would be equal after a time $t$ equal to:

Two radioactive elements $R$ and $S$ disintegrate as
$R \rightarrow P + \alpha; \lambda_R = 4.5 × 10^{-3} \,\, years^{-1}$
$S \rightarrow P + \beta; \lambda_S = 3 × 10^{-3} \,\, years^{-1}$
Starting with number of atoms of $R$ and $S$ in the ratio of $2 : 1,$ this ratio after the lapse of three half lives of $R$ will be :

Choose the correct statement $(s)$ related to the motion of object and its image in the case of mirrors

Three charges $-\mathrm{q}_1,+\mathrm{q}_2$ and $-q_3$ are placed as shown in the figure. The x-component of the force on $-q_3$ is proportional to

There is a current of $40$ ampere in a wire of ${10^{ - 6}}\,{m^2}$ area of cross-section. If the number of free electron per ${m^3}$ is ${10^{29}}$, then the drift velocity will be

The angular momentum of electrons in an atom produces:

A cut diamond sparkles because of its

The sensitivity of a tangent galvanometer is increased if

A cylindrical conductor of radius $'R'$ carries a current $'i'$. The value of magnetic field at a point which is $R/4$ distance inside from the surface is $10\, T$. Find the value of magnetic field at point which is $4\,R$ distance outside from the surface