Test: Physics Mock Test - 2 - NEET MCQ

Explanation:

Given:
- Current flowing through the wire: I = 3t² + 2t + 5
- Time interval: t = 0 to t = 2 sec

Charge Flowing Through the Cross-Section of the Wire:
- The charge flowing through the wire is given by the integral of current with respect to time.
- Q = ∫(3t² + 2t + 5) dt
- Q = [t³ + t² + 5t] evaluated from t = 0 to t = 2 sec
- Q = [(2)³ + (2)² + 5(2)] - [(0)³ + (0)² + 5(0)]
- Q = [8 + 4 + 10] - [0 + 0 + 0]
- Q = 22 C

Therefore, the charge flowing through the cross-section of the wire from t = 0 to t = 2 sec is 22 Coulombs. Hence, the correct answer is A: 22C.

Explanation:

• Electric Flux: The electric flux through a closed surface is given by the total electric field passing through that surface.


• Gauss's Law: According to Gauss's Law, the total electric flux through a closed surface is equal to the total charge enclosed by that surface divided by the permittivity of free space (ε₀).


• Given Situation: In this case, there are eight dipoles of charges inside a cube. Since dipoles consist of equal and opposite charges separated by a distance, the total charge enclosed by the cube is zero.


• Total Electric Flux: Therefore, the total electric flux coming out of the cube is zero as there is no net charge enclosed.


• Therefore, the correct answer is A: zero.


 

CONCEPT: 

The Resultant of two vectors is given by:

R2 = (A2 + B2 + 2AB cosθ) 

where R is the resultant vector, A and B are the two vectors, and θ is the angle between two vectors.​

Maximum value of R = A + B when θ = 0° 

Minimum value of R = A - B when θ = 180° 

CALCULATION:

Given that Two vectors are 5 units and 10 units

The maximum value of the resultant R = A + B = 10 + 5 = 15 units

The minimum value of the resultant R = A - B = 10 - 5 = 5 units

• The resultant vector can be between 5 to 15 units.
• So the result could not be 4 units.
• Hence the correct answer is option 4.

The mass of the lift is 1000 Kg , the acceleration of 1 m / s^2 and the acceleration due to gravity is 9.8 m / s^2 .

The tensions developed in strings is given as ,

T = mg + ma

===》 1000 × 9.8 + 1000 × 1

=====》 10800 N

Thus , the tensions developed in strings is 10800 N.

Explanation:

• Kinetic energy of the ball:
  - The kinetic energy of the ball changes as it moves up and down in its parabolic path. As the ball rises, its kinetic energy decreases due to gravity acting against its motion, and as it falls back to the ground, its kinetic energy increases again. Therefore, the kinetic energy of the ball is not constant throughout its motion.


• Speed of the ball:
  - The speed of the ball changes continuously as it moves up and down in its parabolic path. It is maximum at the moment of release and decreases to zero at the highest point of its path, then increases again as it falls back down. Therefore, the speed of the ball is not constant.


• Horizontal component of velocity:
  - The horizontal component of velocity remains constant throughout the motion of the ball. This is because there are no horizontal forces acting on the ball once it is released. Therefore, the horizontal component of velocity remains the same until the ball hits the ground.


• Vertical component of velocity:
  - The vertical component of velocity changes as the ball moves up and down. At the moment of release, the vertical component of velocity is at its maximum. As the ball moves upwards, the vertical component of velocity decreases due to the effect of gravity until it reaches zero at the highest point. Then, as the ball falls back down, the vertical component of velocity increases in the downward direction. Therefore, the vertical component of velocity is not constant.