Physics - Online Test
Q1. The amount of energy a capacitor can store is called its
Answer : Option B
Explaination / Solution:
Energy stored in a capacitor
Q2. When a mass is rotating in a plane about a fixed point, its angular momentum is directed along
Answer : Option B
Explaination / Solution:
cular to both
and that is along the axis of rotation according to right hand screw rule.
Q3. A wooden block is taken to the bottom of a deep, calm lake of water and then released. It rises up with a
Answer : Option B
Explaination / Solution:
The wooden block rises up with acceleration,
a =
Upthrust and mass of block will be constant.So the acceleration will also be a constant throughout mo
Q4.
In constructing a large mobile, an artist hangs an aluminum sphere of mass 6.0 kg from a vertical steel wire 0.50 m long and 2.5 in cross-sectional area. On the bottom of the sphere he attaches a similar steel wire, from which he hangs a brass cube of mass 10.0 kg. Compute the tensile strain.
Answer : Option A
Explaination / Solution:
No Explaination.
Q5. An observer looks at a tree of height 15 metre with a telescope of magnifying power 10. To him, the tree appears
Answer : Option B
Explaination / Solution:
No Explaination.
Q6.
has a half life of 5 days. The time taken for seven-eighth of a sample to decay is
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. A washer consists of a 3.00 cm diameter circle of sheet metal with a 1.00 cm diameter circular hole in the middle. If the metal washer is heated until the diameter of the washer is 3.03 cm, then the diameter of the hole will be
Answer : Option D
Explaination / Solution:
diameter of hole = 1+0.01 = 1.01cm
Q8. Approximately How many light years is a meter?
Answer : Option D
Explaination / Solution:
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to
=> 1 Light Year =
=> 1 m =
Q9. The current amplitude in a pure inductor in a radio receiver is to be 250 μA when the voltage amplitude is 3.60 V at a frequency of 1.60 MHz (at the upper end of the AM broadcast band). Inductance needed is
Answer : Option B
Explaination / Solution:
f = 1.6 MHz = 1.6 x 106 Hz
If only inductor is present in the circuit, then
inductive reactance
inductance
Q10. Electromotive force is
Answer : Option A
Explaination / Solution:
An electric field exists in the electrolyte between the positive and negative terminals of the battery. In the external circuit, the current flows from the positive electrode to the negative electrode. To maintain continuity, in the electrolyte, the current (positive charges) flow from the negative electrode (lower potential) to the positive electrode (higher potential). Work done by the source in taking unit positive charge from lower to higher potential is called electromotive force.
