HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

Two cells of emf 1.5 Volt and 2 Volt having respective internal resistances of 1 Ω and 2 Ω are connected in parallel so as to send current in the same direction through an external resistance of 5 Ω. Find the current through the external resistance.

A metallic ring of mass 1 kg has a moment of inertia 1 kg m² when rotating about one of its diameters. It is molten and remolded into a thin uniform disc of the same radius. How much will its moment of inertia be, when rotated about its own axis.

The energy stored in a soap bubble of diameter 6 cm and T = 0.04 N/m is nearly ______.

Why is the surface tension of paints and lubricating oils kept low?

How much amount of work is done in forming a soap bubble of radius r?

Explain the capillary action.

Derive an expression for capillary rise for a liquid having a concave meniscus.

Calculate the rise of water inside a clean glass capillary tube of radius 0.1 mm, when immersed in water of surface tension 7 × 10^-2 N/m. The angle of contact between water and glass is zero, the density of water = 1000 kg/m³, g = 9.8 m/s².

Twenty-seven droplets of water, each of radius 0.1 mm coalesce into a single drop. Find the change in surface energy. Surface tension of water is 0.072 N/m.

A drop of mercury of radius 0.2 cm is broken into 8 droplets of the same size. Find the work done if the surface tension of mercury is 435.5 dyn/cm.

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The mean free path λ of molecules is given by where n is the number of molecules per unit volume and d is the diameter of the molecules. 

Obtain an expression for the orbital magnetic moment of an electron rotating about the nucleus in an atom.

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The length of second's pendulum on the surface of earth is nearly 1 m. Its length on the surface of moon should be [Given: acceleration due to gravity (g) on moon is `1/6` th of that on the earth’s surface]

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Two identical springs of constant k are connected, first in series and then in parallel. A metal block of mass m is suspended from their combination. The ratio of their frequencies of vertical oscillations will be in a ratio

A 15.0 μF capacitor is connected to a 220 V, 50 Hz source. Find the capacitive reactance and the current (rms and peak) in the circuit. If the frequency is doubled, what will happen to the capacitive reactance and the current?

A capacitor of 100 μF, a coil of resistance 50Ω, and an inductance 0.5 H are connected in series with a 110 V-50Hz source. Calculate the rms value of current in the circuit.

Find the capacity of a capacitor which when put in series with a 10Ω resistor makes the power factor equal to 0.5. Assume an 80V-100Hz AC supply.

Find the time required for a 50 Hz alternating current to change its value from zero to the rms value.

State the characteristics of progressive waves.

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Polychromatic (containing many different frequencies) radiation is used in an experiment on the photoelectric effect. The stopping potential ______.