CBSE Class 12 Physics Solids and Fluids Basic Problems

CBSE Class 12 Physics Solids and Fluids Basic Problems. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

1. A wire of length 2l and radius r is stretched without tension along a straight line which is fixed at A and B as shown in the figure. Find the tension in the wire when it is pulled to the position ACB when d<

2. A heavy plank of mass 200 kg habgs on three vertical wires of equal length arranged symmetrically. Find tension in the wires if the middle wire is made of steel and the other two are made of copper. These wires have equal areas of cross-section. Given that the modulus of elasticity of steel is twice that of copper.

3. A rectangular block of a material of 3.0 cm length, 1.0 cm breadth and 8.0 cm height is clamped with its 8.0 cm edge vertical. A horizontal force of 2.4 N is applied at the face end such that the top portion of the block is displaced horizontally. Claculate the displacement if the shear modulus of material of the block is 1.4 × 10⁵ Nm^-2.

4. Find the increase in energy of a brass bar 0.2 m long and of cross-sectional area 1.0 cm² when compressed with a load of 5 kg weight along its length. Young’s modulus of brass is 1.0 × 10¹¹ Nm^–2.

5. Two rods of different materials but of equal cross-section and length 1.0 m each are joined to form a rod of length 2.0 m. The first rod has coefficient of linear expansion as 10^–5 / 0C and Young’s modulus as 3.0 × 10¹⁰ Nm^–2. The second rod has coefficient of linear expansion as 2 × 10^–5/ ºC and Young’s modulus as 1.0 × 10¹⁰ Nm–2. How much stress should be applied to the ends of the composite rod to prevent its expansion when the temperature is raised by 100⁰C.

6. Carbon in the form of graphite is subjected to a pressure of 1.55 × 10¹⁰ Nm^–2 at a high temperature to produce artificial diamond crystals. Find the original volume of the sample which produces a diamond of mass 175 gm. Bulk modulus of graphite is 6.2 × 10¹¹ Nm^–2 and density of diamond is 3.5 gm cm^–3.

7. A solid lead sphere of volume 1.0 m³ is dropped in the ocean to a depth where the water pressure is 4 × 10⁷ N/m². If lead has a bulk modulus of 7.7 × 10⁹ N/m², find the fractional change in the radius of the sphere.

8. A cube of wood supports 200 gm of mass such that it just floats in water. If the cube rises by 2 cm when the mass is removed, find the size of cube.

9. A piece of an alloy of mass 96 gm is prepared by using two metals whose specific gravities are 11.4 and 7.4 respectively. If the weight of alloy is 86 gm in water, find the mass of each metal in alloy.

10. Find the height h upto which a cylindrical vessel of radius r should be filled with a homogeneous liquid such that the force with which the liquid presses on the side of the vessel is equal to the force exerted by the liquid on the bottom of the vessel.

11. Water is flowing through two horizontal pipes of different diameters which are connected together. In the first pipe, the speed of water is 4 m-s^–1 and pressure is 2.0 × 10⁴ newton/metre². Calculate the speed and pressure of water in the second pipe. The diameters of the pipes are 3 cm and 6 cm respectively.

12. A tank having cross-sectional area A is filled with water to a height H. If a hole of cross-sectional area a is made at the bottom of the tank, then find the time taken by the water level to decrease from H₁ to H₂.

13. A piece of an alloy of mass 96 gm is composed of two metals whose specific gravities are 11.4 and 7.4. If the weight of the alloy is 86 gm in water, find the mass of each metal in the alloy.

14. Calculate the rate of flow of glycerine of density 1.25 × 10³ kg/m³ through the conical section of a pipe if the radii of its ends are 0.1 m and 0.04 m and the pressure drop across its length is 10 N/m².

15. A glass rod of diameter d₁ = 1.5 mm is inserted symmetrically into a glass capillary tube with inside diameter d₂ = 2.0 m. Then the whole arrangement is vertically oriented and brought in contact with the surface of water. To what height will the water rise in the capillary?

16. Two spherical soap bubbles coalesce. If V is the consequent change in volume of the contained air and S the change in total surface area, show that 3 PV + 4 ST = 0 Where T is the surface tension of soap bubble and P is atmospheric pressure.

17. Two soap bubbles of radius 1 cm and 2 cm coalcsce to form a single drop under isothermal conditions. Find the radius of bigger drop.

18. Find the life time of a soap bubble of radius R connected with the atmosphere through a capillary of length l and inside radius r. The surface tension is T, and the viscosity is η.

19. A spherical ball of radius 1 × 10^–4 m and density 10⁴ kg/m³ falls freely under gravity through a distance h before entering a tank of water. If after entering the water, the velocity of the ball doesn’t charge find h. The coefficient of viscosity of water is 9.8 × 10^–6 N-sec/m²

20. A vessel, whose bottom has round holes with diameter of 1 mm is filled with water. Assuming that surface tension acting only at holes, find the maximum height to which the water can be filled in the vessel without leakage. Given that surface tension of water is 75 × 10^–3 N/m and g = 10 m/s².