Physics - Online Test
Q1. According to Huygens principle
Answer : Option B
Explaination / Solution:
No Explaination.
Q2. Far axial magnetic field of a solenoid as well as bar magnet vary
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. The direction of the universal gravitational force between particles of masses m1 and m2 is:
Answer : Option B
Explaination / Solution:
since gravitational force is attractive in nature, so if there are two particles of m1 & m2 .
So One Force will be on m1 which will be directed towards m 2. i.e
And other force wiil be on m2 which will be directed towards m 1 i.e
Clearly, It can be seen that Because thsese forces are attracted to each other and direction of each force is opposite to other one.
Q4. doping of semiconductor is the process of
Answer : Option B
Explaination / Solution:
Doping is the process of adding impurities to intrinsic semiconductors to alter their properties. Normally Trivalent and Pentavalent elements are used to dope Silicon and Germanium. When an intrinsic semiconductor is doped with Trivalent impurity it becomes a P-Type semiconductor.
Q5. For motion in 3 dimensions we need
Answer : Option D
Explaination / Solution:
Motion is a change in position of an object with time. In order to specify position, we need to use a reference point and a set of axes. It is convenient to choose a rectangular coordinate system consisting of three mutually perpenducular axes, labelled X-, Y-, and Z- axes.
The point of intersection of these three axes is called origin (O) and serves as the reference point. The coordinates (x, y. z) of an object describe the position of the object with respect to this coordinate system.
To measure time, we position a clock in this system. This coordinate system along with a clock constitutes a frame of reference.
Q6. The direction of propagation of an electromagnetic plane wave is
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. in transverse waves, the constituents of the medium
Answer : Option A
Explaination / Solution:
In transverse wave motion medium particles oscillates or vibrates in a direction perpendicular to the direction of wave propagation to form crest & trough in the wave motion.
Q8. According to Farady's law
Answer : Option D
Explaination / Solution:
The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.
Q9.
In the above experimental set up for studying photoelectric effect, if keeping the frequency of the incident radiation and the accelerating potential fixed, the intensity of light is varied, then
Answer : Option D
Explaination / Solution:
With increase in intensity no. of photon incident increases. So that more electron emitted from metal and photo current increases with increase in intensity.
Q10. the centre of mass of a system of particles moves
Answer : Option B
Explaination / Solution:
The centre of mass of a system of particles moves as if all the mass of the system is concentrated at the centre and all the external forces were applied at that point. In order to ease the calculations involved in the dynamics of an extended body, we treat any extended body as the system of particles, and the motion of centre of mass of the system is calculated by taking the mass of the whole system to be concentrated at the centre of mass and the external forces acting on system are said to be acting on the centre of mass.
