Qstnid -37- Light Incident Normally On A Plane Mirror Attached To A Galvanometer Coil Retraces Backwards As Shown In Fig. 9.36. A Current In The Coil Produces A Deflection Of 3.5° Of The Mirror. What Is The Displacement Of The Reflected Spot Of Light On A Screen Placed 1.5 M Away? <Img Src="\etl\image\esa-cbse-xii\phy-hwh-sb2/c01/1_197ec1bb.jpg" Width="235" Height="107" Border="0"> - 09: Ray Optics And Optical Instruments - Neet-xii-physics

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NEET-XII-Physics

09: Ray Optics And Optical Instruments

II - page 5

Qstn# 37 Prvs-Qstn Next-Qstn

#37
Light incident normally on a plane mirror attached to a galvanometer coil retraces backwards as shown in Fig. 9.36. A current in the coil produces a deflection of 3.5° of the mirror. What is the displacement of the reflected spot of light on a screen placed 1.5 m away?

Ans : Angle of deflection, θ = 3.5°

Distance of the screen from the mirror, D = 1.5 m

The reflected rays get deflected by an amount twice the angle of deflection i.e., 2θ= 7.0°

The displacement (d) of the reflected spot of light on the screen is given as:

Hence, the displacement of the reflected spot of light is 18.4 cm.