# DEBRUP SIR PLEASE HELP!

How many images will be formed when two mirrors are kept perpendicular??

5
7
2
3

Your Answer
d

Correct Answer
b
how it is possible?MY WAS 3.

8)Find the distance traveled by light in 0.01 seconds in km

3X10^5
3X10^10
3X10^7
3X10^6

Your Answer
d

Correct Answer
c

the options are given wrong my ans.was3*103

9)If the angle of incidence is 30 then what is the glance angle of reflection?

30
60
90
depends on angle of reflection

Your Answer
a

Correct Answer
b
what is glance angle of reflection?

10)If f= 20 and v= 30 then u?

15
30
12
14

Your Answer
Not Attempted

Correct Answer
c
my ans. had come u=-60 according to the formula 1/f=1/v-1/u
WHAT ABOUT MY MARKS?

• ## 5 Answers

Angikar Ghosal ·

Your answer for the first question is absolutely correct. 360 degrees/angle in which the two mirrors are kept -1 = 360/90 -1 = 4-1 = 3

• Shreya Satra ·

For question 9 Glance angle of reflection = 90- angle of incidence

• Tamal ·

The first one is 3 might have been a problem while uploading.

For question 8 you are right it is 3X10^6 m thus 3X10^3 km

for 9 glance angle of incidence = 90-angle of incidence.

10. you are correct.... while entering v and u got interchanged...

• Aditi Bhaduri ·

YOUR FIRST ANSWER IS CORRECT .
THE FORMULA IS 360°/X-1 . SO, AS IT HAS BEEN KEPT PERPENDICULAR TO EACH OTHER IT SHOULD BE 90° . SO,
360°/90° - 1 IS 3 . SO , YOUR ANSWER IS CORRECT . YOU SHOULD DESERVE FULL MARKS .

• Aditi Bhaduri ·

YOUR FIRST ANSWER IS CORRECT .
THE FORMULA IS 360°/X-1 . SO, AS IT HAS BEEN KEPT PERPENDICULAR TO EACH OTHER IT SHOULD BE 90° . SO,
360°/90° - 1 IS 3 . SO , YOUR ANSWER IS CORRECT . YOU SHOULD DESERVE FULL MARKS .

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