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A magician during a show makes a glass lens with n = 1.47 disappear in a trough of liquid. What is the refractive index of the liquid? Could the liquid be

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A small bulb is placed at the bottom of a tank containing water to a depth of 80cm. What is the area of the surface of water through which light from the bulb can emerge out? Refractive index of water is 1.33. (Consider the bulb to be a point

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What is the focal length of a convex lens of focal length 30cm in contact with a concave lens of focal length 20cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses. Determine the ‘effective focal length’ of the combination of the two

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A glass lens of refractive index 1.45 disappears when immersed in a liquid. What is the value of refractive index of the

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A beam of light converges at a point P. A concave lens of focal length 16 cm is placed in the path of this beam 12 cm from P. Draw a ray diagram and find the location of the point at which the beam would now

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Out of blue and red light, which is deviated more by a prism? Give reason. (ii) Give the formula that can be used to determine refractive index of material of a prism in minimum deviation

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence

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What type of wavefront will emerge from a (i) point source (ii) distant light

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Define a

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(i) Use Huygens' geometrical construction to show the behaviour of a plane wavefront, (a) passing through a biconvex lens (b) reflected by a concave mirror. (ii) When monochromatic light is incident on a surface separating two media, why does the refracted light have the same frequency as that of the incident

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Consider two coherent sources `S_1 and S_2` producing monochromatic waves to produce interference pattern. Let, the displacement of the wave produced by `S_1` be given by `Y_1 = acosomegat` and the displacement by `S_2` be `Y_2 = acos(omegat +phi)` Find out the expression for the amplitude of the resultant displacement at a point and show that the intensity at that point will be `I = 4a^2 cos^2phi/2` Hence, establish the conditions for constructive and destructive interference.(ii) What is the effect on the interference fringes in Young's double slit experiment when (i) the width of the source slit is increased;

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Four identical monochromatic sources A,B,C,D as shown in the (Fig.) produce waves of the same wavelength λ and are coherent. Two receiver R1 and R2 are at great but equal distaces from B. Which of the two receivers picks up the larger

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A 100W sodium lamp radiates energy uniformly in all directions. The lamp is located at the centre of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is 589 nm. At what rate are the photons delivered to

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Light of frequency 7.21 × 1014 Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 × 105 m/s are ejected from the surface. What is the threshold frequency for photoemission of

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Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the emitter is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Also find the de Broglie wavelength of a neutron, in thermal equilibrium with matter, having an average kinetic energy of (3/2) k T at 300

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Answer the following questions: Every metal has a definite work function. Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic? Why is there an energy distribution of

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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There are two sources of light, each emitting with a power of 100 W. One emits X-rays of wavelength 1nm and the other visible light at 500 nm. Find the ratio of number of photons of X-rays to the photons of visible light of the given

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Ultraviolet light is incident on two photosensitive materials having work function `φ_1 and φ_2 (φ_1 > φ_2 )`. In which of the case will K.E. of emitted electrons be greater?

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A charged rod P attracts rod R where as P repels another charged rod Q. What type of force is developed between Q and

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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