A particular emission line, detected in the light from a galaxy, … - Vidyadip

MCQ

A particular emission line, detected in the light from a galaxy, has a wavelength $\lambda ' = 1.1\lambda $, where $\lambda $ is the proper wavelength of the line. The galaxy distance from us

✓
$1.6 \times {10^9}ly$
B
$0.97 \times {10^9}ly$
C
$2.4 \times {10^9}ly$
D
$1.62 \times {10^{11}}ly$

✓

Answer

Correct option: A.

$1.6 \times {10^9}ly$

a
(a) From Hubble’s law $v = Hr$ where $H = $Hubble’s constant $= 19.3 mm/sec-ly$ and $ r = $

Distance of Galaxy from us.

According to Doppler’s effect speed of Galaxy $v = \frac{{c\Delta \lambda }}{\lambda }$

==> $r = \frac{{c\Delta \lambda }}{{H\lambda }} = \frac{{c \times 0.1\lambda }}{{H\lambda }} = \frac{{0.1\, \times 3 \times {{10}^8}}}{{19.3 \times 3 \times {{10}^{ - 3}}}} = 1.6 \times {10^9}\,ly$

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

NEET STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

When a ray of light is incident normally on one refracting surface of an equilateral prism (Refractive index of the material of the prism $= 1.5$)

The sensitivity of a galvanometer of resistance $406\, ohm$ is decreased by $30\, times$. The shunt used is .................. $\Omega$

A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced $e.m.f.$ is

One end of a slack wire (Young's modulus $Y$, length $L$ and cross-sectional area $A$ ) is clamped to a rigid wall and the other end to a block (mass $m$ ), which rests on a smooth horizontal plane. The block is set in motion with a speed $v$. What is the maximum distance, then the block will travel after the wire becomes taut?

Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is

Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is $5.0 \mathrm{~cm}$. The magnitude of the magnetic field at a point $P$ midway between the wires is __________$\mu \mathrm{T}$ (Given : $\mu_0=4 \pi \times 10^{-7} \mathrm{TmA}^{-1}$ )

The time period of oscillation of a magnet is $2\ sec$ . When it is remagnetised so that its pole strength is $4$ times, its period will be .....$sec$

If a unit positive charge is taken from one point to another over an equipotential surface, then

Oil floating on water looks coloured due to interference of light. What should be the order of magnitude of the thickness of oil layer in order that this effect may be observed ......... $m$

Consider $a$ one-dimensional collision that involves $a$ body of mass $m_1$ originally moving in the positive $x$ direction with speed $v_0$ colliding with a second body of mass $m_2$ originally at rest. The collision could be completely inelastic, with the two bodies sticking together, completely elastic, or somewhere in between. After the collision, $m_1$ moves with velocity $v_1 $ while $m_2$ moves with velocity $v_2$.

$(A)$ $If \,m_1 > m_2$,

$(B)$ $If\, m_1 < m_2$,