List of top Physics Questions asked in CBSE CLASS XII

Obtain approximately the ratio of the nuclear radii of the gold isotope \(^{197}_{ 79} Au \) and the silver isotope \(^{107}_{ 47} Ag\).

A given coin has a mass of 3.0 g. Calculate the nuclear energy that would be required to separate all the neutrons and protons from each other. For simplicity assume that the coin is entirely made of \(^{63}_{ 29}Cu\) atoms (of mass 62.92960 u).

Obtain the binding energy of the nuclei \(^{56}_{26}Fe\) and \( ^{209} _{83} Bi\) in units of MeV from the following data: \(m\) (\(^{56}_{26}Fe\)) = 55.934939 u, \(m\) (\( ^{209} _{83} Bi\)) = 208.980388 u

Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude \(17.0 × 10^{−22} Cm^{-2}\). What is E: 
(a) in the outer region of the first plate, 
(b) in the outer region of the second plate, and (c) between the plates?

Obtain the binding energy (in MeV) of a nitrogen nucleus. \((^{14}_{7}N)\) , given m \((^{14}_{7}N)\) = 14.00307 u

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to \((E_g)_C, (E_g)_{Si}\) and \((E_g)_{Ge}\). Which of the following statements is true?

(a)and(b)show the refraction of a ray in air incident at 60° with the normal to a glass-air and water-air interface, respectively. Predict the angle of refraction in glass when the angle of incidence in water is 45° with the normal to a water-glass interface
 

A 4.5cm needle is placed 12cm away from a convex mirror of focal length 15cm. Give the location of the image and the magnification.Describe what happens as the needle is moved farther from the mirror.