**JAC 11th Physics objective Question 2021**. Jharkhand Academic Council will conduct class 11th Annual Examination in the month of May-June 2021. In the Annual Examination all the question will be objective (1 Mark Each). Here we have described Chapter wise objective question and its answer.

**Ques1**. Electromagnetic force is-

- Attractive in nature
- Repulsive in nature
- Attractive as well as repulsive in nature
- None of these

**Ans:- 3) Attractive as well as repulsive in nature**

**Ques2**. 1 Fermi

- 10
^{-15}mm - 10
^{-15}cm - 10
^{-14}m - 10
^{-15}m

**Ans:-4) 10 ^{-15} m**

**Ques3**. Parsec is the Unit of-

- Time
- Distance
- Frequency
- Speed

**Ans:- 2) Distance**

**Ques4**. 1 a.m.u=………..

- 1.66×10
^{-24}kg - 1.66×10
^{-27}kg - 1.66×10
^{-25}kg - 1.66×10
^{-30}kg

**Ans:- 1) 1.66×10 ^{-24} kg**

**Ques5**. Dimensional formula for the pressure is-

- [ML
^{-1}T^{-2}] - [ML T
^{-2}] - [ML
^{-2}T] - [M
^{-1}L^{-1}T^{-2}]

**Ans:-4) [M ^{-1} L^{-1} T^{-2}]**

**Ques6**. If a man goes 10m towards north and 20m toward east, then his displacement is

- 22.5 m
- 25m
- 25.5 m
- 30m

**Ans:- 1)22.5 m**

**Ques7**. A cyclist moving on a circular track of radius 40m Completes half a revolution in 40 sec. Its average velocity is-

- Zero
- 4 π m s
^{-1} - 2 m s
^{-1} - 8 π m s
^{-1}

**Ans:- 3) 2 m s ^{-1}**

**Ques8**. The motion of a particle is described by the education X=at+bt^{2} Where a=15cm S^{-1} and b=3cm S^{-2} , Its instantaneous velocity at t=3 sec will be

- 33 cm S
^{-1} - 18 cm S
^{-1} - 16 cm S
^{-1} - 32 cm S
^{-2}

**Ans:- 1) 33 cm S ^{-1}**

**Ques9**. The area under acceleration-time graph represents the

- Initial Velocity
- Final Velocity
- Change in Velocity
- Distance travelled

**Ans:- 3) Change in Velocity**

**Ques10**. A vehicle travel half the distance L with speed V_{1} and the other half with speed V_{2}, then its average speed is

- V
_{1}+V_{2}/2 - 2V+V
_{2}/V_{1}+V_{2} - 2V
_{1}V_{2}/V_{1}+V_{2} - L(V
_{1}+V_{2})/V_{1}+V_{2}

**Ans:-3) 2V _{1}V_{2}/V_{1}+V_{2}**

**Ques11**. Two cars A and B are running at velocities of 60 Kmh^{-1}. What is the relative velocity of car A with respect to car B, if both are moving eastward?

- 15 Kmh
^{-1} - 45 Kmh
^{-1} - 60 Kmh
^{-1} - 105 Kmh
^{-1}

**Ans:- 1) 15 Kmh ^{-1}**

**Ques12**. Which of the following is not a property of a null vector?

**A**+**O**=**A****λo**=**O**(When λ in a scalar)**OA**=**A****A**–**A**=**O**

**Ans:- 3) OA=A**

**Ques13**. If **A** is a vector of magnitude 5 units due east. What is the magnitude and direction of a vector – **A**?

- 5 units due east
- 25 units due west
- 25 units due east
- 5 units due west

**Ans:- 2) 25 units due west**

**Ques14**. The relation between the time of flight of projectile T_{f} and the time to reach the maximum height T_{m} is

- T
_{f}=2T_{m} - T
_{f}= T_{m} - T
_{f}= T_{m}/2 - T
_{f}=**√**2(T_{m})

**Ans:- 1)T _{f} =2T_{m}**

**Ques15**. An insect trapped in a circular groove of radius 12 cm moves along the groove steadily and completes 7 revolutions in 100 sec. The linear speed of the insect is

- 4.3 cmS
^{-1} - 5.3 cm S
^{-1} - 6.3 cm S
^{-1} - 7.3 cm S
^{-1}

**Ans:- 2)5.3 cm S ^{-1}**

**Also Read** : **JAC 11th examination 2021**.

**Ques16**. A cyclist bends while taking turn to.

- Reduce Friction
- Generate required centripetal
- Reduce apparent weight
- Reduce speed

**Ans:- 2) Generate required centripetal**

**Ques17**. A stone of mass 1kg is lying on the floor of a train which is accelerating with 1 ms^{-1} . The net force acting on the stone is

- Zero
- 1N
- 5N
- 10N

**Ans:- 2) 1N**

**Ques18**. A book is lying on the table. What is the angle between the action of book on the table and the reaction of the table on the book?

- 0
^{0} - 45
^{0} - 90
^{0} - 180
^{0}

**Ans:-4)180 ^{0}**

**Ques19**. Product of the force and Displacement called

- Energy
- Power
- Momentum
- Work

**Ans:-4) Work**

**Ques20**. A boy lifts a mass of 1 k.g to a height of 1m in 20 sec. The power of the boy is (take g=10m/s^{2})

- 0.1W
- 0.2W
- 0.25W
- 0.5W

**Ans:- 4) 0.5W**

**Ques21**. A ball of mass m collides with a wall with speed ‘V’ and rebounds on the same line with the same speed. If the mass of the wall is taken as infinite, then the work done by the ball on the wall is

- mv
^{2} - Zero
- 1/2mv
^{2} - 2 mv
^{2}

**Ans:- 2) Zero**

**Ques22**. For which of the following does the centre of mass lie outside the body?

- A Pencil
- A Shotput
- A Dice
- A Bangle

**Ans:-4) A Bangle**

**Ques23**. A point mass m is placed inside a spherical shell of radius R and mass M at a distance R/2 from the centre of the shell. The gravitational force exerted by the shell on the point mass is

- GMm/R
^{2} - 2GMm/R
^{2} - Zero
- 4GMm/R
^{2}

**Ans:- 3) Zero**

**Ques24**. The escape velocity of 10g. body from the earth is 11.2 km s^{-1} Ignoring air resistance, the escape velocity of 10 kg of the iron ball from the earth will be

- 0.0112km s
^{-1} - 0.112 km s
^{-1} - 11.2 km s
^{-1} - 0.56 km s
^{-1}

**Ans:- 3) 11.2 km s ^{-1}**

**Ques25**. Stress is a——– quantity.

- Scalar
- Vector
- Tensor
- Dimensionless

**Ans:-4) Dimensionless**

**Ques27**. Which of the following is associated with liquid only and not for gases ?

- Decreases
- Increases
- Becomes Zero
- Remains constant

**Ans:- 1) Decreases**

**Ques27**. Which of the following is associated with liquid only and not for gases?

- Surface tension
- Pressure
- Volume
- Density

**Ans:- 1) Surface tension**

**Ques28**. Application of Bernoulli’s theorem can be seen in

- Dynamic lift of aeroplane
- Hydraulic press
- Helicopter
- None of these

**Ans:-1) Dynamic lift of aeroplane**

**Ques29**. An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters 2.5 cm and 3.75 cm. The ratio of the velocities in the two pipes is

- 9:4
- 3:2
- √3:√2
- √2:√3

**Ans:- 1) 9:4**

**Ques30**. Dimensional formula of Specific heat capacity is.

- [ML
^{2}T^{-2}K] - [ML
^{2}T^{-2}K^{-1}] - [MLT
^{-2}K^{-1}] - [M
^{0}L^{2}T^{2}K^{-1}]

**Ans:-4) [M ^{0}L^{2}T^{2}K^{-1}]**

**Ques31**. Dimensional formula of Specific heat capacity is

- [MLT
^{-2}K^{-1}] - [MLT
^{-3}K^{-1}] - [ML
^{2}T^{-2}K^{-1}] - MLT
^{-3}K]

**Ans:- 2) [MLT ^{-3} K^{-1}]**

JAC 11th Physics Objective Question 2021 Chapter wise.

**Ques32**. A body cools in 7 minutes from 60^{0}C to 40^{0}C. Then what its temperature in next 7 minute? (If the surrounding temperature is 10^{0}C.)

- 20
^{0}C - 30
^{0}C - 28
^{0}C - 35
^{0}C

**Ans:- 3) 28 ^{0}C**

**Ques33**. First law of thermodynamics is the law of conservation of

- Mass
- Lincar momentum
- Energy
- Angular momentum

**Ans:- 3) Energy**

**Ques34**.Internal energy of an isolated system

- Remains the same
- Increases
- Decreases
- None of these

**Ans:- 1) Remains the same**

**Ques35**. Find the efficiency of a Carnot’s engine working between 127^{0}C and 27^{0}C?

- 35%
- 25%
- 50%
- None of these

**Ans:- 20 25%**

**Ques36**. Different of C_{p} and C_{v} is-

- R
- J
- Y
- G

**Ans:- 1) R**

**Ques37**. If the pressure and volume of certain Quantity of ideal gas are half, then its temperature;

- Doubled
- Becomes one-forth
- Remains constant
- Becomes four time

**Ans:- 2) Becomes one-forth**

**Ques38**. Education of a simple harmonic motion is given by- X=10 sin (20t+0.5)

- 3.14 Hz
- 6.28 Hz
- 3.18 Hz
- 1.57 Hz

**Ans:- 3) 3.18 Hz**

**Ques39**. A progressive wave is represented by Y=10 sin (100π t – 2 π x). Where X and Y is in meter, and t is in second. Then maximum particle velocity-

- 100π m/s
- 20π m/s
- 200π m/s
- 1000π m/s

**Ans:- 1000π m/s**

**Ques40**. The doppler effect is applicable for

- Sound waves only
- Light waves only
- Both sound and light waves
- None of these

**Ans:- 3) Both sound and light waves**

Official Website of Jharkhand Board – https://jac.jharkhand.gov.in/jac/.

All the Best for JAC 11th Physics Objective Question 2021.