HSC Science (Electronics) इयत्ता ११ वी - Maharashtra State Board Question Bank Solutions for Physics

Two charges 5 μC and -4μC are kept 5.0 m apart at points A and B respectively. How much work will have to be done to move the charge at A through a distance of 5.0 m further away from point B along the line BA?

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While rotating an object or while opening a door or a water tap we apply a force or forces. Under which conditions is this process easy for us? Why? Define the vector quantity concerned. How does it differ for a single force and for two opposite forces with different lines of action?

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Why is the moment of a couple independent of the axis of rotation even if the axis is fixed?

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Explain the term 'steady state'.

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Define coefficient of thermal conductivity.

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Derive its expression for the coefficient of thermal conductivity.

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Give any four applications of thermal conductivity in everyday life.

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Explain the term thermal resistance. State its SI unit and dimensions.

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How heat transfer occurs through radiation in absence of a medium?

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Which materials can be used as thermal insulators and why?

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Which will require more energy, heating a 2.0 kg block of lead by 30 K or heating a 4.0 kg block of copper by 5 K?
(s_lead = 128 J kg^–1 K^–1, `"s"_"copper"` = 387 J kg^–1 K^–1)

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The rate of flow of heat through a copper rod with temperature difference 30 °C is 1500 cal/s. Find the thermal resistance of copper rod.

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An electric kettle takes 20 minutes to heat a certain quantity of water from 0 °C to boiling point. It requires 90 minutes to turn all the water at 100 °C into steam. Find the latent heat of vaporization. (Specific heat of water = 1 cal/g °C)

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Find the temperature difference between two sides of a steel plate 4 cm thick, when the heat is transmitted through the plate at the rate of 400 k cal per minute per square meter at a steady state. Thermal conductivity of steel is 0.026 kcal/m s K.

Explain balancing or mechanical equilibrium. The linear velocity of a rotating fan as a whole is generally zero. Is it in mechanical equilibrium? Justify your answer.

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A 2 m long wooden plank of mass 20 kg is pivoted (supported from below) at 0.5 m from either end. A person of mass 40 kg starts walking from one of these pivots to the farther end. How far can the person walk before the plank topples?

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A 2 m long ladder of mass 10 kg is kept against a wall such that its base is 1.2 m away from the wall. The wall is smooth but the ground is rough. The roughness of the ground is such that it offers a maximum horizontal resistive force (for sliding motion) half that of normal reaction at the point of contact. A monkey of mass 20 kg starts climbing the ladder. How far can it climb along the ladder? How much is the horizontal reaction at the wall?

The distance between two bodies is doubled. How is the magnitude of the gravitational force between them affected?

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Why do we need to know the center of mass of an object? For which objects, its position may differ from that of the center of gravity?

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State Newton’s law of cooling and explain how it can be experimentally verified.