CBSE 11TH PHYSICS - Online Test
Q1. As a ball rises the vertical component of its velocity
Answer : Option C
Explaination / Solution:
if a ball is thrown upward at an angle? The ball has a vertical and a horizontal component of velocity. The force of gravity is acting on it and its acceleration is in the downward direction. The vertical component of velocity is therefore changing. As the motion and acceleration is in opposite direction so vertical component of velocity decrease.
Q2. A lead cube measures 6.00 cm on each side. The bottom face is held in place by very strong glue to a flat horizontal surface, while a horizontal force F is applied to the upper face parallel to one of the edges. How large must F be to cause the cube to deform by 0.250 mm? (Shear modulus of lead = 0.6 Pa)
Answer : Option B
Explaination / Solution:
No Explaination.
Q3.
A 3.00-g copper penny at 25.0C drops from a height of 50.0 m to the ground. (a) If 60.0percent of the change in potential energy goes into increasing the internal energy, what is its final temperature? Specific heat of Cu
Answer : Option A
Explaination / Solution:
Heat used in increasing temp
Q4. Figure shows the position-time graph of a particle of mass 4 kg. What is the force on the particle for ?
Answer : Option C
Explaination / Solution:
When t < 0. As this part is horizontal, thus it can be concluded that distance covered by the particle is zero and hence force on the particle is zero.
When 0 < t < 4 s. As OA has a constant slope, hence in this interval, particle moves with constant velocity (acceleration = 0). Hence force on the particle is zero.
W'hen t > 4s. As this portion shows that particle always remains at a distance of 3 m from the origin i.e., the particle is at rest. Hence force on the particle is zero.
Q5. The launching mechanism of a toy gun consists of a spring of unknown spring constant. When the spring is compressed 0.120 m, the gun, when fired vertically, is able to launch a 35.0-g projectile to a maximum height of 20.0 m above the position of the projectile before firing. Neglecting all resistive forces, determine the spring constant.
Answer : Option A
Explaination / Solution:
Potential energy of spring converted in to potential energy
Q6. The sun releases energy coming from
Answer : Option B
Explaination / Solution:
In addition to intense heat, there is an incredible amount of pressure at the Sun's core. In fact, the vast amounts of hydrogen atoms in the Sun's core are compressed and heated so much that they fuse together.
This reaction, known as nuclear fusion, converts hydrogen atoms into helium. The by-product of nuclear fusion in the Sun's core is a massive volume of energy that gets released and radiates outward toward the surface of the Sun and then into the solar system beyond it.
Q7. A ring of radius r and mass m rotates about its central axis. The kinetic energy is
Answer : Option C
Explaination / Solution:
Q8. An air bubble of radius r is formed inside a tank of water of depth h. The atmospheric pressure is equal to a water column of height H. the pressure inside the bubble is
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. A cylinder contains a mixture of helium and argon gas in equilibrium at 150C. What is the average kinetic energy for each type of gas molecule?
Answer : Option A
Explaination / Solution:
Average KE depends only on temperature
Q10. A ‘thermacole’ icebox is a cheap and efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 C, and co-efficient of thermal conductivity of thermacole is 0.01 J . [Heat of fusion of water = 335 ]
Answer : Option D
Explaination / Solution:
A = Surface area of the box = 6s2 = 6 × (0.3)2 = 0.54 m3
Time gap, t = 6 h = 6 × 60 × 60 s
But Q = m'L
∴ m' = Q/L
= 104976/(335 × 103) = 0.313 kg
Mass of ice left = 4 – 0.3 = 3.7 kg
Hence, the amount of ice remaining after 6 h is 3.7 kg.
