Latest Elitmus Aptitude Question SOLUTION: Four mirrors are erected perpendicular to the ground to from a rectangle ABCD (where A,B,C,D are four corners of the Rectangle ) the longer mirror are of length 15cms and shorter

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(#M40152802) ELITMUS Category question Keep an EYE

Four mirrors are erected perpendicular to the ground to from a rectangle ABCD (where A,B,C,D are four corners of the

Rectangle ) the longer mirror are of length 15cms and shorter mirrors are of length 4cms the reflective surface of all

Mirrors are facing inwards and there is negligible gap b/w two mirrors at the four corners through which nothing more than

a laser beam is shot at mirror BC(longer mirror)through the gap at point A. In a plane parallel to the ground.

Q1 How many times will the laser beam bounce off a mirror surface before exiting the rectangle from point C , if the beam

travels a total distance of 25cm inside the rectangle.
A) 5 B) 4 C)3 D)none

Q2) How many times will the laser beam bounce off a mirror surface before exiting the rectangle from point A, if the beam

Travels the shortest possible distance inside the rectanagle.
A)22 B)15 C)4 D)none

Asked In Elitmus JUGAL KHAJURIYA (8 years ago)

Unsolved Read Solution (7)

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Read Solution (7) :

bhawana  (8 years ago)

1. b, it has to reflect 4 times before exiting the point A
2. d, It has to reflect 2 times before exiting

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ravisha aggarwal  (8 years ago)

1. ans= 5 reason: divide 15cm into 5 parts of 3 cm each. first the ray strikes at 3 cm then 6cm then final exiting at point c.

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Ajitesh rai  (8 years ago)

@ Ravish Aggarwal...
Your solution is correct...but the Answer is 4
As the no of times it will bounce is 4

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chaitalibanerjee  (8 years ago)

Can u plz xpln how

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prashant shekhar singfh  (8 years ago)

Q1 B) 4
Q2 B) 15

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amit kumar sahu  (8 years ago)

1st=5
2nd=unsolved

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dewanand sahu  (6 years ago)

u see a doubt comes usually in mind that which angle it is projected to traverse totally 25cm in before exiting through C. thinking in terms of geometry usually we deal with 30/45/60 degrees. so lets we have one side 4cm of rectangle and 25 is a multiple of 5 so if a laser is projected at 3cm with 30degree a hypotenuse of 5 is created which will be the path of light everytime it bounces back so total 4 times bouncing will happen. think and ponder for a while as if why these values are given 4,5,25 relation between them in geometry(pythagoras theorem)

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