The distance between the virtual image from its real object is 60 cm in case of a concave mirror and the image formed is 3 times magnified. What is the magnitude of focal length (in textcm ) of the mirror?

Question

The distance between the virtual image from its real object is 60 cm in case of a concave mirror and the image formed is 3 times magnified. What is the magnitude of focal length (in textcm ) of the mirror? (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-poqd4q6frw06.png" /> x + 3x=60 ⇒ x=15 cm u=-15 cm m=+ 3 ∴ m=(f/f - u)⇒ + 3=(f/f - (. - 15 .)) ∴ 3f+ 45=f ⇒ f=- 22.5 cm |f|=22.5cm

Q. The distance between the virtual image from its real object is $60 c m$ in case of a concave mirror and the image formed is $3$ times magnified. What is the magnitude of focal length (in $cm$ ) of the mirror?

$x + 3 x = 60 \Rightarrow x = 15 c m$
$u = - 15 c m$
$m = + 3$
$∴ m = \frac{f}{f - u} \Rightarrow + 3 = \frac{f}{f - ( - 15 )}$
$∴ 3 f + 45 = f \Rightarrow f = - 22.5 c m$
$∣ f ∣ = 22.5 c m$

Q. The distance between the virtual image from its real object is 60cm in case of a concave mirror and the image formed is 3 times magnified. What is the magnitude of focal length (in cm ) of the mirror?

x+3x=60⇒x=15cm u=−15cm m=+3 ∴m=f−uf​⇒+3=f−(−15)f​ ∴3f+45=f⇒f=−22.5cm ∣f∣=22.5cm

Q. The distance between the virtual image from its real object is $60 c m$ in case of a concave mirror and the image formed is $3$ times magnified. What is the magnitude of focal length (in $cm$ ) of the mirror?

$x + 3 x = 60 \Rightarrow x = 15 c m$
$u = - 15 c m$
$m = + 3$
$∴ m = \frac{f}{f - u} \Rightarrow + 3 = \frac{f}{f - ( - 15 )}$
$∴ 3 f + 45 = f \Rightarrow f = - 22.5 c m$
$∣ f ∣ = 22.5 c m$