AIPMT 2011 Solved Papers
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Physics 2011
Q. 36. The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is
(1) 2 (2) 3
(3) 4 (4) 1
Sol.
Answer : (1)
Q.37. Which of the following is not due to total internal reflection?
(1) Brilliance of diamond
(2) Working of optical fibre
(3) Difference between apparent and real depth of a pond
(4) Mirage on hot summer days
Sol.
Real & apparent depth are explained on the basis of refraction only. TIR not involved here.
Answer : (3)
Q. 38. A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options describe best the image formed of an object of height 2 cm placed 30 cm from the lens?
(1) Real, inverted, height = 1 cm (2) Virtual, upright, height = 1 cm
(3) Virtual, upright, height = 0.5 cm (4) Real, inverted, height = 4 cm
Sol.
In general we have assumed µ = 1.5,
So, f = 20 cm and calculate v = 60 cm
Answer : (4)
Q. 39. In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is
(1) 2.3 V (2) 1.8 V
(3) 1.3 V (4) 0.5 V
Sol.
eV = KEmax
Answer : (4)
Q. 40. Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 km then the de-Broglie wavelength associated with the electrons would
(1) Increase by 4 times (2) Increase by 2 times
(3) Decrease by 2 times (4) Decrease by 4 times
Sol.
Answer : (3)