Q. In a thin film of oil on water, which color of light is most likely to be reflected? (2022)
A.Red
B.Blue
C.Green
D.Yellow
Solution
Due to the phenomenon of thin film interference, the color that is most prominently reflected depends on the thickness of the film and the wavelength of light. Typically, blue light is more likely to be reflected due to shorter wavelengths.
Q. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that it causes constructive interference for red light? (2022)
A.Red
B.Blue
C.Green
D.Yellow
Solution
The color that appears at the center of the pattern corresponds to the wavelength that experiences constructive interference, which in this case is red light.
Q. In a thin film of oil on water, which color will appear at the center of the pattern if the film is viewed in white light? (2022)
A.Red
B.Blue
C.Green
D.Yellow
Solution
At the center of the thin film interference pattern, the color that appears is typically green due to the constructive interference of wavelengths in that range.
Q. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that it causes constructive interference for blue light? (2022)
A.Red
B.Green
C.Blue
D.Yellow
Solution
If the film thickness causes constructive interference for blue light, blue will appear at the center of the pattern.
Q. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that it causes destructive interference for red light? (2022)
A.Blue
B.Green
C.Yellow
D.Red
Solution
Destructive interference for red light means red light is canceled out, leaving the shorter wavelengths (blue) visible.
Q. In a uniform magnetic field, a charged particle moves in a circular path. What is the relationship between the radius of the path and the speed of the particle? (2022)
A.Directly proportional
B.Inversely proportional
C.No relation
D.Quadratic relation
Solution
The radius of the circular path is directly proportional to the speed of the charged particle in a uniform magnetic field.
Q. In a uniform magnetic field, the magnetic force on a current-carrying conductor is maximum when the angle between the conductor and the field is: (2019)
A.0 degrees
B.90 degrees
C.45 degrees
D.180 degrees
Solution
The magnetic force is maximum when the angle between the conductor and the magnetic field is 90 degrees, as sin(90°) = 1.
Q. In a zero-order reaction, the rate of reaction is independent of the concentration of the reactants. What is the unit of the rate constant (k) for a zero-order reaction? (2023)
A.mol/L·s
B.L^2/mol·s
C.mol/L
D.s^-1
Solution
For a zero-order reaction, the rate is constant and does not depend on the concentration of reactants. The unit of the rate constant (k) is mol/L·s.