Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Physics

50 cc of oxygen is collected in an inverted gas jar over water. The atmospheric pressure is 99.4 kPa and the room temperature is 27°C. The water level in the jar is same as the level outside. The saturation vapour pressure at 27°C is 3.4 kPa. Calculate the number of moles of oxygen collected in the jar.

A 100 W bulb has tungsten filament of total length 1.0 m and radius 4 × 10⁻⁵ m. The emissivity of the filament is 0.8 and σ = 6.0 × 10⁻⁸ W m⁻²K⁴. Calculate the temperature of the filament when the bulb is operating at correct wattage.

A spherical tungsten piece of radius 1.0 cm is suspended in an evacuated chamber maintained at 300 K. The piece is maintained at 1000 K by heating it electrically. Find the rate at which the electrical energy must be supplied. The emissivity of tungsten is 0.30 and the Stefan constant σ is 6.0 × 10⁻⁸ W m⁻² K⁻⁴.

A sphere, a cube and a thin circular plate, all of the same material and same mass are initially heated to same high temperature. 

A uniform disc of radius R, is resting on a table on its rim.The coefficient of friction between disc and table is µ (Figure). Now the disc is pulled with a force F as shown in the figure. What is the maximum value of F for which the disc rolls without slipping?

‘Gulab Jamuns’ (assumed to be spherical) are to be heated in an oven. They are available in two sizes, one twice bigger (in radius) than the other. Pizzas (assumed to be discs) are also to be heated in oven. They are also in two sizes, one twice big (in radius) than the other. All four are put together to be heated to oven temperature. Choose the correct option from the following:

1. Both size gulab jamuns will get heated in the same time.
2. Smaller gulab jamuns are heated before bigger ones.
3. Smaller pizzas are heated before bigger ones.
4. Bigger pizzas are heated before smaller ones.

In the following example of motion, can the body be considered approximately a point object:

A monkey sitting on top of a man cycling smoothly on a circular track.

In the following example of motion, can the body be considered approximately a point object:

A spinning cricket ball that turns sharply on hitting the ground.

In the following example of motion, can the body be considered approximately a point object:

A tumbling beaker that has slipped off the edge of a table.

Look at the graph carefully and state, with reason, that this cannot possibly represent the one-dimensional motion of a particle.

Look at the graph carefully and state, with reason, that this cannot possibly represent the one-dimensional motion of a particle.

Look at the graph carefully and state, with reason, that this cannot possibly represent the one-dimensional motion of a particle.

Some washing machines have cloth driers. It contains a drum in which wet clothes are kept. As the drum rotates, the water particles get separated from the cloth. The general description of this action is that "the centrifugal force throws the water particles away from the drum". Comment on this statement from the viewpoint of an observer rotating with the drum and the observer who is washing the clothes.

A small coin is placed on a record rotating at \[33\frac{1}{3}\] rev/minute. The coin does not slip on the record. Where does it get the required centripetal force from ?

After a good meal at a party you wash your hands and find that you have forgotten to bring your handkerchief. You shake your hand vigorously to remove the water as much as you can. Why is water removed in this process?

Consider the circular motion of the Earth around the sun. Which of the following statements is more appropriate?

(a) Gravitational attraction of the sun on the earth is equal to the centripetal force.
(b) The gravitational attraction of the sun on the earth is the centripetal force.

A heavy mass m is hanging from a string in equilibrium without breaking it. When this same mass is set into oscillation, the string breaks. Explain. 

A particle of mass m is observed from an inertial frame of reference and is found to move in a circle of radius r with a uniform speed v. The centrifugal force on it is 

A particle of mass m rotates with a uniform angular speed ω. It is viewed from a frame rotating about the Z-axis with a uniform angular speed ω₀. The centrifugal force on the particle is