NEET Physics MCQs

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:

Given the value of Rydberg constants is ${\rm{1}}{{\rm{0}}^7}\,{{\rm{m}}^{ - 1}}$, the wave number of the last line of the Balmer series in hydrogen spectrum will be:

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)

Given the value of Rydberg constants is ${\rm{1}}{{\rm{0}}^7}\,{{\rm{m}}^{ - 1}}$, the wave number of the last line of the Balmer series in hydrogen spectrum will be:

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:

For CE transistor amplifier, the audio signal voltage across the collector resistance of $2\,k\Omega$ is $4\,V$. If the current amplification factor of the transistor is 100 and the base resistance is $1k\,\Omega$, then the input signal voltage 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:

A npn transistor is connected in common emitter configuration in a given amplifier. A load resistance of $800\,\Omega$ is connected in the collector circuit and the voltage drop across it is 0.8 V. If the current amplification factor is 0.96 and the input resistance of the circuit is $192\,\Omega$ , the voltage gain and the power gain of the amplifier will respectively 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: