Physics - Online Test
Q1. Simple harmonic motion is the projection of _____________________ of the circle in which the latter motion takes place.
Answer : Option B
Explaination / Solution:
Simple harmonic motion is the projection of uniform circular motion.In the above diagram P is the position of particle at at any instant of time.This motion follows the condition of SHM.simple harmonic motion is a type of periodic motion or oscillation motion where the restoring force is directly proportional to the displacement and acts in the direction opposite to that of displacement
Q2. Approximate Doppler shift formula for light is
Answer : Option D
Explaination / Solution:
No Explaination.
Q3.
According to the dipole analogy corresponds to
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. To find the resultant gravitational force acting on the particle m due to a number of masses we need to use:
Answer : Option C
Explaination / Solution:
According to properties of gravitational force, gravitational force between the particles is independent of the presence or absence of other particles; so the principle of superposition is valid i.e. force on a particle due to number of particles is the resultant of forces due to individual particles i.e.
Q5. In n-type semiconductor the fifth electron
Answer : Option B
Explaination / Solution:
When we add a small quantity of impurity in a semiconductor than the impurity contributes either free electrons or holes to the semiconductor. As a result, the conducting property of semiconductor changes. The process of changing the conductive property of semiconductor by adding impurities is known as doping.
Suppose, in any pure or intrinsic germanium or silicon semiconductor any pentavalent impurity is added. The pentavalent impurities are those which have atoms with five (5) valence electrons. As soon as we add the impurity to the semiconductor, the impurity atoms will replace some of the semiconductor atoms in the crystal structure.
Now four (4) of the five (5) valance electrons of impurity atom will involve in bonding with four neighborhood semiconductor atoms, but the fifth one electron will not find any place to occupy.
This fifth electron of the impurity atom can be made available as free electron or negative charge carrier even if a very small amount of energy is applied.
Q6. An object is said to be in uniform motion in a straight line if its displacement
Answer : Option B
Explaination / Solution:
Uniform motion is the kind of motion in which a body covers equal displacement in equal intervals of time. It does not matter how small the time intervals are, as long as the displacements covered are equal.
If a body is involved in rectilinear motion and the motion is uniform, then the acceleration of the body must be zero.
Q7. In plane electromagnetic wave propagation velocity V, wavelength λ and frequency ϑ are related by
Answer : Option C
Explaination / Solution:
No Explaination.
Q8. The waves on the surface of water are of two kinds:.
Answer : Option D
Explaination / Solution:
As capillary & gravity waves are elastic waves or mechanical waves which require medium for their propagation.
Hence they are using the elastic behaviour of water.
Hence
The waves on the surface of water are of two kinds:
capillary waves and gravity waves
Q9. According to Lenz’s law
Answer : Option B
Explaination / Solution:
Direction of an induced emf, or the current, in any circuit is such as to oppose the cause that produce it.
If the direction of the induced current were such as not to oppose then we would be obtaining electrical energy continuously without doing work, which is impossible
Q10. In various experiments on photo electricity the stopping potential for a given frequency of the incident radiation
Answer : Option B
Explaination / Solution:
The stopping potential is defined as the potential necessary to stop any electron even the electron with the most kinetic energy from reaching the other plate. By changing radiation intensity only no.of emitted electron changes their Kinetic energy will not change.
