Reflection

A bus driver looks into a plane mirror 20 cm long which is placed 50 cm in front of him. If the rear window is 500 cm away from the plane mirror, through what length of the rear window can he see whenever he looks into the mirror while he is driving?

well Im totally confused aout this question.. is the answer 550cm?? :confused:

Reply 1

e-n-i-g-m-a

hey !! can anyone help ?/

Reply 2

BCHL85

can't understand your question... 20cm long of the mirror for what?

Reply 3

e-n-i-g-m-a

the length of the plane mirror is 20 cm

Reply 4

BCHL85

I think in the bus they use concave mirror? So it might be the radius of the sphere?

Reply 5

e-n-i-g-m-a

BCHL85

I think in the bus they use concave mirror? So it might be the radius of the sphere?

UMM .. i dont think so

Reply 6

BCHL85

Alright ... the question ask about what length of the rear window he can see, not distance between him and the image of the window. So it's not that easy to say 550cm

Reply 7

VCVT17

I think you should use the principle of the refection of mirror:
the angle of the light come in with the line perpendicular to the mirror is equal to the angle of the light come out with that line.
So the further distance the is 20/50 = x /500
x = 200 cm
But actually, he can also see around the area contain mirror. So the actual distance he can view is:
200 + 20 = 220 cm

If the answer is 550 cm??? I think maybe you read the question wrong??? So if a plane mirror is 50 cm long which is placed 20 cm in front of him and distance of real window is 200 cm.
So the answer will come out with = 500 + 50 cm