Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Physics

Which of the following statement is true?

Which of the following statements is false for a perfect conductor?

Two a-particles have the ratio of their velocities as 3 : 2 on entering the field. If they move in different circular paths, then the ratio of the radii of their paths is ______.

Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator is ______.

Identify the wrong statement.

Three Charges 2q, -q and -q lie at vertices of a triangle. The value of E and V at centroid of triangle will be ______.

A solid spherical conductor has charge +Q and radius R. It is surrounded by a solid spherical shell with charge -Q, inner radius 2R, and outer radius 3R. Which of the following statements is true?

Hydrogen spectrum consists of discrete bright lines in a dark background and it is specifically known as hydrogen emission spectrum. There is one more type of hydrogen spectrum that exists where we get dark lines on the bright background, it is known as absorption spectrum. Balmer found an empirical formula by the observation of a small part of this spectrum and it is represented by

`1/lambda = "R"(1/2^2 - 1/"n"^2)`, where n = 3, 4, 5,....

For Lyman series, the emission is from first state to n^th state, for Paschen series, it is from third state to n^th state, for Brackett series, it is from fourth state to n^th state and for P fund series, it is from fifth state to n^th state.

Number of spectral lines in hydrogen atom is ______.

Hydrogen spectrum consists of discrete bright lines in a dark background and it is specifically known as hydrogen emission spectrum. There is one more type of hydrogen spectrum that exists where we get dark lines on the bright background, it is known as the absorption spectrum. Balmer found an empirical formula by the observation of a small part of this spectrum and it is represented by

`1/lambda = "R"(1/2^2 - 1/"n"^2)`, where n = 3, 4, 5,....

For Lyman series, the emission is from first state to n^th state, for Paschen series, it is from third state to n^th state, for Brackett series, it is from fourth state to n^th state and for P fund series, it is from fifth state to n^th state.

Which series of hydrogen spectrum corresponds to ultraviolet region?

Hydrogen spectrum consists of discrete bright lines in a dark background and it is specifically known as hydrogen emission spectrum. There is one more type of hydrogen spectrum that exists where we get dark lines on the bright background, it is known as absorption spectrum. Balmer found an empirical formula by the observation of a small part of this spectrum and it is represented by

`1/lambda = "R"(1/2^2 - 1/"n"^2)`, where n = 3, 4, 5,....

For Lyman series, the emission is from first state to n^th state, for Paschen series, it is from third state to n^th state, for Brackett series, it is from fourth state to n^th state and for P fund series, it is from fifth state to n^th state.

Which of the following lines of the H-atom spectrum belongs to the Balmer series?

Hydrogen spectrum consists of discrete bright lines in a dark background and it is specifically known as hydrogen emission spectrum. There is one more type of hydrogen spectrum that exists where we get dark lines on the bright background, it is known as absorption spectrum. Balmer found an empirical formula by the observation of a small part of this spectrum and it is represented by

`1/lambda = "R"(1/2^2 - 1/"n"^2)`, where n = 3, 4, 5,....

For Lyman series, the emission is from first state to n^th state, for Paschen series, it is from third state to n^th state, for Brackett series, it is from fourth state to n^th state and for P fund series, it is from fifth state to n^th state.

Rydberg constant is ______.

What are eddy currents?

Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV.

What is the kinetic energy (in eV) of the fastest electrons emitted from the surface?

Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV.

What will be the change in the energy of the emitted electrons if the intensity of light with same wavelength is doubled?

Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV.

If the same light falls on another surface of work function 6.5 eV, what will be the energy of emitted electrons?

A test charge q is made to move in the electric field of a point charge Q along two different closed paths (Figure). First path has sections along and perpendicular to lines of electric field. Second path is a rectangular loop of the same area as the first loop. How does the work done compare in the two cases?

Two cells of emf’s approximately 5V and 10V are to be accurately compared using a potentiometer of length 400 cm.

First a set of n equal resistors of R each are connected in series to a battery of emf E and internal resistance R. A current I is observed to flow. Then the n resistors are connected in parallel to the same battery. It is observed that the current is increased 10 times. What is ‘n’?