Physics - Online Test
Q1. In old age, arteries carrying blood in the human body, become narrow resulting in an increase in the blood pressure. This follows from
Answer : Option D
Explaination / Solution:
According to bernoulli principle for fluids: in ideal state pressure and density are inversely related or in other words a slow moving fluid exerts more pressure than a fast moving fluid. Due to narrowness and other obstruction the velocity of the flow of blood gets decreased in old age. This results in increased pressure inside the blood vessel.
Q2.
Air at 20.0 in the cylinder of a diesel engine is compressed from an initial pressure of 1.00 atm and volume of 800.0 to a volume of 60.0 . Assume that air behaves as an ideal gas with and that the compression is adiabatic. Find the final pressure of the air
Answer : Option A
Explaination / Solution:
P1V1γ=P2V2γP2=P1(V1V2)γ=1×(80060)1.4=37.6atm
Q3. The largest telescope in the world has a reflector with an aperture of 200 inches in order to achieve
Answer : Option B
Explaination / Solution:
No Explaination.
Q4. The half life of radon is 3.8 days. After how many days will only one twentieth of a radon sample be left over?
Answer : Option A
Explaination / Solution:
No Explaination.
Q5. Molar Specific Heat capacity has units of
Answer : Option B
Explaination / Solution:
Q=nCΔTC=QnΔT
Q6. A new unit of length is chosen such that the speed of light in vacuum is unity. What is the distance between the Sun and the Earth in terms of the new unit if light takes 8 min and 20 s to cover this distance?
Answer : Option D
Explaination / Solution:
Distance between the Sun and the Earth = Speed of light ×Time taken by light to cover the distance
Given that in the new unit,
speed of light = 1 unit
Time taken, t = 8 min 20 s = 500 s Distance between the Sun and the Earth = 1 x 500 = 500 units
Q7. A hair dryer meant for 110V, 60Hz is to be used in India . If 220 V is the supply voltage in India , the turns ratio for a transformer would be
Answer : Option B
Explaination / Solution:
the ratio between the number of primary turns to the number of secondary turns being called the “turns ratio” or “transformer ratio”.
turn ratio is
, hence it is a step down transformer.
Q8. Current density of a conductor is
Answer : Option B
Explaination / Solution:
Current density J = I/A
In electromagnetism, current density is the electric current per unit area of cross section. It is a vector and has a direction along the area vector.
Q9. In the arrangement shown in the figure, if the block of mass m is displaced, the frequency is given by
Answer : Option A
Explaination / Solution:
No Explaination.
Q10. A circular coil of radius R carries an electric current. The magnetic field due to the coil at a point on the axis of the coil located at a distance r from the center of the coil such that r>>R, varies as
Answer : Option B
Explaination / Solution:
At a point distance r from the coil, the magnetic field is . If is neglected in the denominator;
