A converging lens has a focal length of 5cm. Determine its power
+20.0
+0.2
-20.00
-0.2
Correct answer is A
p = \(\frac{100}{f} = \frac{100}{+5} = +20\)
2.35m
1.35m
1.00m
0.35m
Correct answer is B
n = \(\frac{R.d}{A.d}\)
1.35 = \(\frac{R.d}{1}\)
R.d = 1.35m
100cm
33cm
29cm
20cm
Correct answer is D
M = \(\frac{v}{u}\)
v = mu = 4 x 25 = 100m
\(\frac{1}{v} + \frac{1}{u} = \frac{1}{f}\)
\(\frac{1}{100} + \frac{1}{25} = \frac{1}{f}\)
f = 20cm
real and magnified
real and inverted
erect and magnified
erect and virtual
Correct answer is B
No explanation has been provided for this answer.
The image which cannot be formed on a screen is said to be
inverted
erect
real
virtual
Correct answer is D
Any image that can be formed on a screen are called real image. Such images are formed by light rays emanating from the object, when reflected and/or refracted by devices such as lenses and mirrors converge at some specific point.
In contrast there are other images which are formed by the rays of light reaching the observer appearing to converge at some point. This happens when the rays reaching the observer are diverging and when the line of these rays are projected backward. Such images, which cannot be formed on a screen, are called virtual image.