Physics - Online Test
Q1. The volume of a cube of side 2 cm is equal in to
Answer : Option D
Explaination / Solution:
Side of cube (a) = 2 cm =
Volume of cube (V) =
=
Q2. A circuit containing a 80 mH inductor and a 60 μF capacitor in series is connected to a 230 V, 50 Hz supply. The resistance of the circuit is negligible. Average powers transferred to the inductor and to the capacitor are respectively
Answer : Option C
Explaination / Solution:
average power consumed by inductor is zero as actual voltage leads the current by
average power consumed by capacitor is zero as actual voltage lags the current by
Q3. A capacitor is charged and then made to discharge through a resistance. The time constant is τ. In what time will the potential difference across the capacitor decreases by 10%?
Answer : Option D
Explaination / Solution:
The capacitance of a capacitor is a constant.
Also, V q
The discharging equation for capacitor is
A similar equation can be written for potential difference.
Q4. The kinetic energy of a body executing S.H.M. is 1/3 of the potential energy. Then, the displacement of the body is x percent of the amplitude, where x is
Answer : Option D
Explaination / Solution:
No Explaination.
Q5. If D and f are the objective diameter, and focal length, Minimum separation, , in the object plane of a compound microscope that can be resolved is given by
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. If the area under the B-H curve of a material M is more, in an ac solenoid using material M
Answer : Option A
Explaination / Solution:
No Explaination.
Q7. When arsenic is added as an impurity to silicon, the resulting material is
Answer : Option A
Explaination / Solution:
Doping is the process of intentionally introducing impurities into an extremely pure (i.e., intrinsic) semiconductor in order to change its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic semiconductor. A semiconductor which is doped to such high levels that it acts more like a conductor than a semiconductor is called degenerate.
Dopant atoms can either be “donors” or “acceptors.” Donors increase the elctron concentration in the silicon, whereas acceptors increase the hole concentration.
When Arsenic crystal is doped with silicone atoms, then it becomes N-type.
Q8. in which of the following examples of motion, can the body be considered approximately a point object?
Answer : Option C
Explaination / Solution:
Point object is an expression used in kinematics branch of physics: it is an object whose dimensions are ignored or neglected while considering its motion.
The size of a carriage is very small as compared to the distance between two stations. Therefore, the carriage can be treated as a point sized object.
Q9. The human ear is most sensitive to sound in the frequency range of
Answer : Option A
Explaination / Solution:
No Explaination.
Q10. Calculate the electric and magnetic fields produced by the radiation coming from a 100 W bulb at a distance of 3 m. Assume that the efficiency of the bulb is 2.5% and it is a point source
Answer : Option B
Explaination / Solution:
No Explaination.
