Dual-Nature-Of-Radiation-and-Matter-Quiz-10

Dual Nature Of Radiation and Matter Quiz-10

Dear Readers,

As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background. 

Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced. 

Q91. Compton effect shows that

•  X-rays are waves
•  X-rays have high energy
•  X-rays can penetrate matter
•  Photons have momentum

Solution
Photons have momentum

Q92.Which one of the following statements regarding photo-emission of electrons is correct?

•  Kinetic energy of electrons increases with the intensity of incident light.
•  Electrons are emitted when the wavelength of the incident light is above a certain threshold wavelength.
•  Photoelectric emission is instantaneous with the incidence of light.
•  Photoelectrons are emitted whenever a gas is irradiated with ultraviolet light.

Solution
KE of photoelectrons increases with increase in frequency of the incident light and is independent of the intensity of incident light. Photoelectrons are emitted if the wavelength of the incident light is less than threshold wavelength, as ϕ₀=hc/λ₀ Photoelectric emission is an instantaneous process photoelectrons may not be emitted from a gas with ultraviolet light if the work function of that gas is large than the energy UV light

Q93.  If n_R and n_V denote the number of photons emitted by a red bulb and violet bulb of equal power in a given time, then

•   n_R=n_V
•  n_R>n_V
•  n_R<n_V
•  n_R≥n_V

Solution
                   

 

Q94. An X-ray machine is operated at 40 kV. The short wavelength limit of continuous X-rays will be (h=6.63×10^-34 Js,c = 3×10⁸ ms^^-1,e=1.6×10^-19 C)

•  0.31Å
•  0.62Å
•  0.155Å
•  0.62Å

Solution
                              

Q95. The threshold frequency for certain metal is 3.3×10^14 Hz. If light of frequency 8.2×10¹⁴ Hz is incident on the metal, the cut-off voltage of the photoelectric current will be

•  4.9 V
•  3.0 V
•  2.0 V
•  1V

Solution
                    

Q96. The work function for metals A,B and C are respectively 1.92 eV,2.0 eV and 5 eV. According to Einstein’s equation, the metals which will emit photo electrons for a radiation of wavelength 4100 Å is/are

•  None of these
• A only
•  A and B only
•  All the three metals

Solution
In an electric field, a force opposite to the direction of electric field acts on negatively charged particles (i.e. from lower potential to higher potential)

Q97.A beam of light of wavelength λ and with illumination L falls on a clean surface of sodium. If N photoelectrons are emitted each with kinetic energy E, then

•  N∝L and E∝L
•  N∝L and E∝1/λ
•  N∝λ and E∝L
•  N∝1/λ and E∝1/L

Solution
Number of photons emitted is proportional to the intensity. Also hc/λ=W₀+E

Q98.Light of wavelength 5000Å is falling on a sensitive surface.If the surface has received 10^-7 J of energy, then the number
of photons falling on the surface will be

•  5×10¹¹
•  2.5×10¹¹
•  3×10¹¹
•  None of these

Solution
                            

Q99.A proton and an α-particle are accelerated through a potential difference of 100 V. The ratio of the wavelength associated
with the proton to that associated with an α-particle is

•  √2 ∶1
•  2 ∶1
•  2√2 ∶1
•  1/(2√2):1

Solution
                            

Q100. A electron moving with a variable linear velocity v in a variable magnetic field B will remain rotating in a circle of constant radius r only when

•  B is held constant
•  v is held constant
•  Both v and B are constant
• None of these

Solution
For a charged particle in magnetic field B,r=m v/qB. The radius can be fixed for a charged particle if v and B both are fixed