Henry is the unit of :

A person can see clearly only upto a distance of 25 cm. He wants to read a book placed at a distance of 50 cm. What kind of lens does he require for his spectacles and what must be its power

(a) Concave, – 1.0 D

(b) Convex, + 1.5 D

(d) Convex, + 2.0 D

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The ratio of speed of an electron in ground state in Bohrs first orbit of hydrogen atom to velocity of light in air is

(a)

(b)

(c)

(d)

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Which experiment seemed to make it clear that light propogates as a wave?

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The presently accepted value of charge/ mass (e/ m) is:

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Consider three converging lenses L₁, L₂ and L₃ having identical geometrical construction. The index of refraction of L₁ and L₂ are $\mu_1$ and $\mu_2$ respectively. The upper half of the lens L₃ has a refractive index $\mu_1$ and the lower half has $\mu_2$. A point object O is imaged at O₁ by the lens L₁ and at O₂ by the lens L₂ placed in same position. If L₃ is placed at the same place:

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A proton and an alpha particle are separately projected in a region where a uniform magnetic field exists. Their initial velocities are perpendicular to direction of magnetic field. If both the particles move around magnetic field in circles of equal radii, the ratio of momentum of proton to alpha particle is