List of top Physics Questions

Focal plane of a spherical mirror is
When a set of parallel rays of light inclined at 15° to the principal axis, are incident on a convex lens, they
To find normal to a curved surface at a point, join that point and
A transistor amplifier along with a tank circuit with positive feedback will act as
In p-type semiconductors
If the mass numbers of two nuclei are in the ratio 3: 2, then the ratio of their nuclear densities is :
The ratio of the total energy E of the electron to its kinetic energy K in hydrogen atom is
1018 fissions per second is required for producing power of 300 MW in a nuclear power station. To increase the power output to 360 MW the additional number of fissions required per second is
During $ẞ^{-}$ decay of a radioactive element there is an increase in its
If the momentum of an α-particle is half that of a proton, then the ratio between the wavelengths of their de-Broglie waves is
If $θ_p$ is the polarizing angle for a glass plate of refractive index μ and critical angle $θ_c$, then
In Young's double-slit experiment, two different light beams of wavelengths $λ_1$ and $λ_2$ produce interference pattern with band widths $β_1$ and $β_2$ respectively. If the ratio between $β_1$ and $β_2$ is 3:2, then the ratio between and is
An object is placed at 10 cm in front of a concave mirror. If the image is at 20 cm from the mirror on the same side of the object, then the magnification produced by the mirror is
The apparent depth of a needle lying in a water beaker is found to be 9 cm. If water is replaced by a liquid of refractive index 1.5, then the apparent depth of needle will be (μ of water is 4/3)
Fresnel distance for an aperture of size a illuminated by a parallel beam of light of wavelength λ, deciding the validity of ray optics is
Three phtodiodes D1, D2, D3 are made of semiconductors having band gaps of 2.5 eV, 2 eV and 3 eV respectively. Which one will be able to detect light of wavelength 600 nm?
Identify the incorrect statement :
In a nuclear reactor heavy nuclei is not used as moderators because
Which graph in the following diagram correctly represents the potential energy of a pair of nucleons as a function of their separation?
An electron in an excited state of Li2+ ion has angular momentum \(\frac{3h}{2\pi}\). The de Broglie wavelength of electron in this state is Pπa0 (where a0 = Boh r radius). The value of P is
The figure shows standing de Broglie waves due to the revolution of electron in a certain orbit of hydrogen atom. Then the expression for the orbit radius is (all notations have their usual meanings)
de Broglie waves due to the revolution of electron in a certain orbit of hydrogen atom
Energy of an electron in the second orbit of hydrogen atom is E2. The energy of electron in the third orbit of He+ will be
According to Einstein’s photoelectric equation to the graph between kinetic energy of photoelectrons ejected and the frequency of incident radiation is
A proton moving with a momentum P1 has a kinetic energy \(\frac{1}{8}th\) of its rest mass energy. Another light photon having energy equal to the kinetic energy of the possesses a momentum P2. Then the ratio \(\frac{P_1-P_2}{P_1}\) is equal to
The work function of a metal is 1eV. Light of wavelength 3000Å is incident on this metal surface. The velocity of emitted photoelectrons will be