A laser beam has a power of 100 mW. It has an aperture of `5xx10^(-3)`m and emits a wavelength 6943 Å. The beam is focused with a lens of focal length 0.1 m. Calculate the areal spread and intensity of the image.
1 Answers
Prove that `^100 C_2^(100)C_2+^(100)C_2^(100)C_4+^(100)C_4^(100)C_6++^(100)C_(98)^(100)C_(100)=1/2[^(200)C_(98)-^(100)C_(49)]dot`
To find `S = .^(100)C_(0).^(100)C_(2)+.^(100)C_(2).^(100)C_(4)+.^(100)C_(4).^(100)C_(6)+"....."+.^(100)C_(98).^(100)C_(100)` Consider, `.^(100)C_(0).^(100)C_(2)+.^(100)C_(1).^(100)C_(3) + .^(100)C_(2).^(100)C_(4)+.^(100)C_(3)+.^(100)C_(5)+"...." + .^(100)C_(98).^(100)C_(100)` `= .^(100)C_(0).^(100)C_(98)+.^(100)C_(1).^(100)C_(97) + .^(100)C_(2).^(100)C_(96)+.^(100)C_(3).^(100)C_(95) + "....."+^(100)C_(98) .^(100)C_(0)` = Coefficients of `x^(98)` in `(1+x)^(100) (1+x)^(100)` `= .^(200)C_(98) " "(1)` Also,...
2 Answers 1 views
A `0.6 xx 10^(-3) W` laser is aimed at the Moon. The wavelength of emitted light is 600 nm and the laser beam spreads out of the source at a divergenc
Correct Answer - `5.7 xx 10^(4) m^(-2) s^(-1)`
2 Answers 1 views
An eye-piece consists of a concave lens of focal length 2f and a convex lens of focal length 3f separted by a distance `(f)/(2)`. They are of the same
Correct Answer - Free from chromatic aberration but not spherical, yes
2 Answers 1 views
Calculate the focal length of a convex lens of crown glass of dispersive power 0.012 and concave lens of dispersive power 0.020 that from an achromati
Correct Answer - `r_("common")=1.11 m,0.644m`
2 Answers 2 views
A beam of light of wavelength 590 nm is focused by a convex lens of diameter 10 cm at a distance of 20 cm from it. Find the diameter of the disc image
Correct Answer - `5.6xx10^(-4)`cm
2 Answers 1 views
A laser beam has a wavelength of `6xx10^(-7)`m and aperture of `6xx10^(-2)`m. The beam is sent towards the moon which is at a distance of `4xx10^(8)`m
Correct Answer - (i)`1.22xx10^(-5)rad(ii) 2.381xx10^(7)`m
2 Answers 1 views
An object is placed `12 cm` to the left of a diverging lens of focal length `-6.0 cm.` A converging lens with a focal length of `12.0 cm` is placed at
Correct Answer - 8 cm
2 Answers 1 views
A compound lens has been formed by joinined a convex and a concave lens, each of focal length 30 cm. what is the focal length of the combination? What
Correct Answer - Infinite, zero
2 Answers 1 views
Find the focal length and power of a convex lens, which when placed in contact with a concave lens of focal length `25 cm` forms a real image `5` time
Correct Answer - 10 cm, 10D
2 Answers 1 views
If first wave of feminism was focused on Right to vote, the second wave of feminism was focused on
A) Education and health
2 Answers 1 views