Tags Physics

Physics

Get insights from 5.6k questions on Physics, answered by students, alumni, and experts. You may also ask and answer any question you like about Physics

Follow Ask Question

5.6k

Questions

Discussions

Active Users

Followers

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A, B and C are three non-collinear, non co-planar vectors. What can you say about direction of A * (B * C)?

0 Follower 5 Views

alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation – the direction of (B $* C$ ) will be perpendicular the plane containing B and B by right hand rule. A $* (B * C)$ will lie in the plane of B and C and is perpendicular to vector A.

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 11th Chapter Thirteen

An inflated rubber balloon contains one mole of an ideal gas, has a pressure p, volume V and temperature T. If the temperature rises to 1.1 T, and the volume is increased to 1.05 V, the final pressure will be

(a) 1.1 p

(b) p

(c) Less than p

(d) Between p and 1.1

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

(d) pV=nRT

So n= PV/RT

As number moles are fixed

$\frac{P_{1} V_{1}}{{R T}_{1}} = \frac{P_{1} V_{1}}{{R T}_{1}}$

P₂=p₁V₁ (T₂/V₂T₁)

= $\frac{p V ((1.1 T))}{1.05 V ((T))}$

= P $* \frac{1.1}{1.05} \approx 1.05 P$

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A football is kicked into the air vertically upwards. What is its (a) acceleration, and (b) velocity at the highest point?

0 Follower 2 Views

alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- if the football is kicked into the air vertically upwards. Acceleration of football will always vertically downwards and equal to acceleration due to gravity. But when it reaches the highest point its velocity is zero and acceleration is retarding.

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A ball is thrown from a roof top at an angle of 45° above the horizontal. It hits the ground a few seconds later. At what point during its motion, does the ball have

(a) Greatest speed.

(b) Smallest speed.

(c) Greatest acceleration? Explain

0 Follower 7 Views

alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- at point B it will gain the same speed u and after that speed increases and will be maximum just before reaching point c.

During journey from O to A speed decreases and will be maximum at point A and acceleration is always constant.

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 11th Chapter Thirteen

A vessel of volume V contains a mixture of 1 mole of Hydrogen and 1 mole of Oxygen (both considered as ideal). Let f₁(v)dv, denote the fraction of molecules with speed between v and (v + dv) with f₂(v)dv, similarly for oxygen. Then

(a) f₁(v) + f₂(v) = f(v) obeys the Maxwell's distribution law

(b) f₁(v), f₂(v)will obey the Maxwell's distribution law separately

(c) Neither f₁(v), nor f₂(v) will obey the Maxwell's distribution law

(d) f₂(v) and f1 (v) will be the same

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

(b) For a function f (v), the number of molecules n=f (v) which are having speeds between v and v+dv

So f₁ (v) and f₂ (v) will obey's maxwell distribution law

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 11th Chapter Thirteen

1 mole of H₂ gas is contained in a box of volume V = 1.00 m³ at T = 300K. The gas is heated to a temperature of T = 3000K and the gas gets converted to a gas of hydrogen atoms. The final pressure would be (considering all gases to be ideal)

(a) Same as the pressure initially

(b) 2 times the pressure initially

(c) 10 times the pressure initially

(d) 20 times the pressure initially

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

(d) When number of molecules breaks then number of moles would become double.

P $\propto n T$ where n is the number of moles and T is temperature of ideal gas

As gases breaks number of moles becomes twcice of initial so n₂ =2n₁

$\frac{P_{2}}{P_{1}} = \frac{n_{2} T_{2}}{n_{1} T_{1}} = \frac{2 n_{1} (3000)}{n_{1} (300)}$ = 20

p₂=20p₁

so 20 times

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A particle is projected in air at some angle to the horizontal, moves along parabola as shown in Fig., where x and y indicate horizontal and vertical directions, respectively. Show in the diagram, direction of velocity and acceleration at points A, B and C.

0 Follower 5 Views

alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- vsin $θ$ = vertical component

V_x= horizontal component of velocity =vcos $θ$ = constant

V_y = vertical component of velocity =vsin $θ$

Velocity will always be tangential to the curve in the direction of motion and acceleration is always vertically downward and is equal to g.

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A cyclist starts from centre O of a circular park of radius 1km and moves along the path OPRQO as shown Fig. 4.3. If he maintains constant speed of 10ms–1, what is his acceleration at point R in magnitude and direction?

0 Follower 1 View

alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- the cyclist covers OPRQO path.

As we know whenever an object performing circular motion, acceleration is called centripetal acceleration and is always directed towards the centre.

so there will be centripetal acceleration a= v²/r

So a= 100/1km= 100/1000=0.1m/s² along RO.

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 11th Chapter Thirteen

Volume versus temperature graphs for a given mass of an ideal gas are shown in Fig. at two different values of constant pressure. What can be inferred about relation between p₁ & p₂?

(a) p₁ > p₂

(b) p₁ = p₂

(c) p₁ < p₂

(d) Data is insufficient.

0 Follower 5 Views

Payal Gupta

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

(a) Pressure is inversely proportional to slope

So $p_{1}$ $p$ $2 = \frac{m_{2}}{m_{1}} <1$

So p₁ > p₂

0 0

New answer posted

10 months ago

Physics Physics NCERT Exemplar Solutions Class 12th Chapter Four

A man wants to reach from A to the opposite corner of the square C (Fig. 4.10). The sides of the square are 100 m. A central square of 50m * 50m is filled with sand. Outside this square, he can walk at a speed 1 m/s. In the central square, he can walk only at a speed of v m/s (v < 1). What is smallest value of v for which he can reach faster via a straight path through the sand than any path in the square outside the sand?