How does the frequency of a beam of ultraviolet light change when it goes from air to glass?

Two metals A and B have work functions 4eV and 10eV respectively. Which metal has higher threshold wavelength?

Why is \(n\)-type semiconductor of Ge so called?

Give the names of the Indian satellites launched from the erstwhile USSR for remote sensing

What happens to light energy when light waves interfere destructively at a point?

What is the range of frequencies used for TV transmission?What is common between these waves and light waves?

A charged Particle q is shot towards another charged particle Q which is fixed , with a speed v. It approaches Q up to a closet distance r and then returns, If q were given a speed 2 v the n find the closet distance of approach.

The refractive index of water is 4/3. Obtain the value of the semivertical angle of the cone within which the entire outside view would be confined for a fish under water. Draw an appropriate ray diagram

An object is placed at (i) 10 cm, (ii) 5 cm in front of a concave mirror of radius of curvature 15 cm. Find the position, nature, and magnification of the image in each case.

(a) A point object is placed in front of a double convex lens (of refractive index n =n₂/n₁ with respect air) with its spherical faces of radii of curvature R₁ and R_2.. Show the path of rays due to surface to obtain the formation of the real image of the object.
Hence obtain the lens maker's formula for a thin lens.
(b) A double convex lens having both faces of the same radius of curvature has refractive index 1.55. Find out the radius of curvature of the lens required to get the focal length of 20 cm.

Dimpi's class was shown a video on effects of magnetic field on a current carrying straight conductor. She noticed that the force on the straight current carrying conductor becomes zero when it is oriented parallel to the magnetic field and this force becomes maximum when it is perpendicular to the field. She shared this interesting information with her grandfather in the evening. The grandfather could immediately relate it to something similar in real life situations. He explained it to Dimpi that similar things happen in real life too. When we align and orient our thinking and actions in an adaptive and accommodating way our lives become more peaceful and happy. However, when we adopt an unaccommodating and stubborn attitude, life becomes troubled and miserable. We should therefore always be careful in our response to different situations in life and avoid unnecessary conflicts.
Answer the following based on above information:
(a) Express the force acting on a straight current carrying conductor kept in a magnetic field in vector form. State the rule used to find the direction of this force.
(b) Which one value is displayed and conveyed by the grandfather as well as Dimpi?
(c) Mention one specific situation from your own life which reflects similar values shown by you towards your elders.

Einstein was the first to establish the equivalence between mass energy. According to him, whenever a certain mass \(\left( \Delta m \right) \) disappears in some process, the amount of energy released is \(E=\left( \Delta m \right) { c }^{ 2 },\) where c is velocity of light vacuum \(\left( =3\times { 10 }^{ 8 }m/s \right) .\) The reverse is also true, i.e., whenever energy E disappears, an equivalent mass \(\left( \Delta m \right) ={ E/c }^{ 2 }\) appears.
Read the above passage and answer the following questions :
(i) What is the energy released when 1 a.m.u. of mass disappears in a nuclear reaction?
(ii) Do you know any phenomenon in which energy materialises?
(iii) What values of life do you learn from this famous relation?

A Cassegrain telescope uses two mirrors as shown in Figure. Such a telescope is built with the mirrors 20 mm apart. If the radius of curvature of the large mirror is 220mm and the small mirror is 140mm, where will the final image of an object at infinity be?

A cube of side b has a charge q at each of its vertices.Determine the potential and electric field due to this charge array at the centre of the cube.

The extent of localisation of a particle is determined by its de-Broglie wavelength.If an electron is localised within the nucleus(of size about \({ 10 }^{ -14 }\))of an atom, what is it energy? Compare this energy with the typical binding energies(of the order of a few MeV) in a nucleus and hence argue why electron cannot reside in a nucleus.