CBSE 11TH PHYSICS - Online Test
Q1. A stone tied to the end of a string 80 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 s, what is the magnitude and direction of acceleration of the stone?
Answer : Option C
Explaination / Solution:
Length of the string, l = 80 cm = 0.8 m
Number of revolutions = 14
Time taken = 25 s
Frequency,
Angular frequency,
=
Centripetal acceleration, ac = ω2r
=
= 9.9 ms-2
The direction of centripetal acceleration is always directed along the string, towards the centre, at all points.
Number of revolutions = 14
Time taken = 25 s
Frequency,
Angular frequency,
=
Centripetal acceleration, ac = ω2r
=
= 9.9 ms-2
The direction of centripetal acceleration is always directed along the string, towards the centre, at all points.
Q2. A hydraulic press contains 0.25 (250 L) of oil. Find the decrease in the volume of the oil when it is subjected to a pressure increase = 1.6 Pa(about 160 atm or 2300 psi). The bulk modulus of the oil is B = 5.0 Pa
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. What is the change in the temperature of the gas?
Answer : Option C
Explaination / Solution:
Temperature remains constant because system is thermally insulated. so that change in temperature will be zero.
Q4. A body of mass 0.40 kg moving initially with a constant speed of 10 m /s to the north is subject to a constant force of 8.0 N directed towards the south for 30 s. Take the instant the force is applied to be t = 0, the position of the body at that time to be x = 0, and predict its position at t = –5 s.
Answer : Option B
Explaination / Solution:
Let ,
At t= -5 s, there is no force acting on the particle,
so,
Q5. A rain drop of mass 2.00 g falls from a height 1.00 km. It hits the ground with a speed of 50.0 m/s. What is the work done by the gravitational force? (Take g = 10 m )
Answer : Option C
Explaination / Solution:
W=Fscosθ=mghcos0∘W=2×10−3×10×1000×1=20J
Q6. The major contribution of M.N. Saha was
Answer : Option C
Explaination / Solution:
Meghnad Saha was an eminent Indian astrophysicist who gave the world the theory of ionization which explained the origin of stellar spectra.
Q7. Which of the following has the largest moment of inertia?
Answer : Option A
Explaination / Solution:
Hence ring has largest moment of inertia.
Q8. 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.
Q9.
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
Q10. Molar Specific Heat capacity has units of
Answer : Option B
Explaination / Solution:
Q=nCΔTC=QnΔT
