Work, Energy, Power and Collision - CBSE STD 12 Science JEE physics Questions

Q 1Assertion & Reason1 Mark

Assertion : Soft steel can be made red hot by continued hammering on it, but hard steel cannot.
Reason : Energy transfer in case of soft iron is large as in hard steel.

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Q 2Assertion & Reason1 Mark

Assertion : Mountain roads rarely go straight up the slope.
Reason : Slope of mountains are large therefore more chances of vehicle to slip from roads.

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Q 3Assertion & Reason1 Mark

Assertion : A work done in moving a body over a closed loop is zero for every force in nature.
Reason : Work done does not depend on nature of force.

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Q 4Assertion & Reason1 Mark

Assertion : Power of machine gun is determined by both, the number of bullet fired per second and kinetic energy of bullets.
Reason : Power of any machine is defined as work done (by it) per unit time.

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Q 5Assertion & Reason1 Mark

Assertion : In case of bullet fired from gun, the ratio of kinetic energy of gun and bullet is equal to ratio of mass of bullet and gun.
Reason : In firing, momentum is conserved.

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Q 6MCQ1 Mark

Four smooth steel balls of equal mass at rest are free to move along a straight line without friction. The first ball is given a velocity of $0.4 \mathrm{~m} / \mathrm{s}$. It collides head on with the second elastically, the second one similarly with the third and so on. The velocity of the last ball is

✓
$0.4 \mathrm{~m} / \mathrm{s}$
B
$0.2 \mathrm{~m} / \mathrm{s}$
C
$0.1 \mathrm{~m} / \mathrm{s}$
D
$0.05 \mathrm{~m} / \mathrm{s}$

Answer: A.

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Q 7MCQ1 Mark

Consider elastic collision of a particle of mass $m$ moving with a velocity $u$ with another particle of the same mass at rest. After the collision the projectile and the struck particle move in directions making angles $\theta_1$ and $\theta_2$ respectively with the initial direction of motion. The sum of the angles. $\theta_1+\theta_2$, is

A
$45^{\circ}$
✓
$90^{\circ}$
C
$135^{\circ}$
D
$180^{\circ}$

Answer: B.

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Q 8MCQ1 Mark

An object of mass $3 \mathrm{~m}$ splits into three equal fragments. Two fragments have velocities $\hat{v j}$ and $\hat{v i}$. The velocity of the third fragment is

A
$v(\hat{j}-\hat{i})$
B
$v(\hat{i}-\hat{j})$
✓
$-v(\hat{i}+\hat{j})$
D
$\frac{v(\hat{i}+\hat{j})}{\sqrt{2}}$

Answer: C.

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Q 9MCQ1 Mark

$1$ a.m.u. is equivalent to

A
$1.6 \times 10^{-12}$ Joule
B
$1.6 \times 10^{-19}$ Joule
✓
$1.5 \times 10^{-10}$ Joule
D
$1.5 \times 10^{-19}$ Joule

Answer: C.

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Q 10MCQ1 Mark

A particle of mass ' $m$ ' and charge ' $q$ ' is accelerated through a potential difference of ' $\mathrm{V}$ ' volt. Its energy is

✓
$q V$
B
$m q V$
C
$\left(\frac{q}{m}\right) V$
D
$\frac{q}{m V}$

Answer: A.

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Work, Energy, Power and Collision question types

Work, Energy, Power and Collision questions

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Work, Energy, Power and Collision JEE physics - Work, Energy, Power and Collision

Work, Energy, Power and Collision question types

Work, Energy, Power and Collision questions

Generate a Work, Energy, Power and Collision paper free