NEET Physics MCQs

In a diffraction pattern due to a single slit of width ‘a’, the first minimum is observed at an angle ${30^{\rm{o}}}$ when light of wavelength 5000 $\mathop {\rm{A}}\limits^{\rm{o}}$ is incident on the slit. The first secondary maximum is observed at an angle of:

Electrons of mass m with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cutoff wavelength $({\lambda _0})$ of the emitted X-ray is:

Photons with energy $5{\mkern 1mu} {\mkern 1mu} \,eV$ incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is $2\,e{\mkern 1mu} V$. When photons of energy $6\,eV$ are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is:

An electron of mass m and a photon have same energy E. the ratio of de-Brogile wavelengths associated with them is:

SS

(c being velocity of light)

When a metallic surface is illuminated with radiation of wavelength $\lambda$, the stopping potential is V. If the same surface is illuminated with radiation of wavelength $2\lambda$, the stopping potential is $\frac{{\rm{v}}}{4}$. The threshold wavelength for the metallic surface is:

If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength $\lambda$. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be:

If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength $\lambda$. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be:

When an ${\rm{\alpha }}$ - particle of mass ‘m’ moving with the velocity ‘v’ bombards on a heavy nucleus of charge ‘Ze’, its distance of closest approach from the nucleus depends on m as:

Electrons of mass m with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cutoff wavelength $({\lambda _0})$ of the emitted X-ray is:

When an ${\rm{\alpha }}$ - particle of mass ‘m’ moving with the velocity ‘v’ bombards on a heavy nucleus of charge ‘Ze’, its distance of closest approach from the nucleus depends on m as: