Answer

Verified

401.4k+ views

**Hint:**To solve this problem, first find the gravitational force acting on the plate. For doing this, use the formula for gravitational force. Substitute the values and calculate its value. Then, use the relationship between power and force to obtain the equation for force exerted by a light beam in terms of velocity and power. At equilibrium, gravitational force is equal to the force exerted by a light beam. Substitute the values and find the power of the light beam.

**Complete answer:**

Given: Mass of the plate (m)= 10 g= $10 \times {10}^{-3} kg$

Gravitational force acting on the plate is given by,

${F}_{gravitational}= mg$

Substituting values in above equation we get,

${F}_{gravitational}= 10 \times {10}^{-3} \times 10$

$\Rightarrow{F}_{gravitational}= {10}^{-1} N$ ...(1)

The relationship between power and force is given by,

$P= Fv$ ...(2)

Where, F is the force exerted

v is the velocity of the object

Rearranging equation. (2) we get,

$F= \dfrac {P}{v}$ ...(3)

Here, the object is light. Light moves with velocity c. So, equation. (3) can be written as,

${F}_{light}= \dfrac {P}{c}$ ...(4)

At equilibrium, force exerted by the light beam should be equal to the gravitational force.

$\Rightarrow {F}_{light}= {F}_{gravitational}$

Substituting values in above equation we get,

$\dfrac {P}{c}= {10}^{-1}$

$\Rightarrow \dfrac {P}{3 \times {10}^{8}}= {10}^{-1}$

$\Rightarrow P= 3 \times {10}^{8} \times {10}^{-1}$

$\Rightarrow P= 3 \times {10}^{7}$

Hence, power of the beam is $3 \times {10}^{7}$ W.

**So, the correct answer is option A i.e. $3 \times {10}^{7} W$.**

**Note:**

Students should take care of the unit conversion. They should check whether the units are balanced or not. If not then they should convert the units of the quantities to their S.I. units. Not converting the units to their S.I. units will give them a wrong output altogether. Students should also take care of the powers while doing the calculations.

Recently Updated Pages

How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE

Mark and label the given geoinformation on the outline class 11 social science CBSE

When people say No pun intended what does that mea class 8 english CBSE

Name the states which share their boundary with Indias class 9 social science CBSE

Give an account of the Northern Plains of India class 9 social science CBSE

Change the following sentences into negative and interrogative class 10 english CBSE

Trending doubts

Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE

Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE

Fill the blanks with the suitable prepositions 1 The class 9 english CBSE

Difference Between Plant Cell and Animal Cell

Which are the Top 10 Largest Countries of the World?

Write a letter to the principal requesting him to grant class 10 english CBSE

10 examples of evaporation in daily life with explanations

Give 10 examples for herbs , shrubs , climbers , creepers

Change the following sentences into negative and interrogative class 10 english CBSE