A ladder has rungs 25 cm apart.(see Fig.)The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top.If the top and the bottom rungs are `2(1/2)m'apart.What is the length of the wood required for the rungs?

How would you combine two lens of focal length 25cm to 2.5 cm to make a telescope?

A rod of 2 cm in height is held in front of a convex lens. The, image formed at a distance 60 cm and object at 10 cm from the mirror. What is the focal length of the lens ?

A person cannot see objects nearer than 1.2 m from his eyes. He wants for read a newspaper placed at a distance of 30 cm clearly. What is the nature and the power of lens required for this purpose?

A bucket made up of a metal sheet is in the form of a frustum of a cone. Its depth is 24 cm and the diameters of the top and bottom are 30 cm and 10 cm respectively. Find the cost of milk which can completely fill the bucket at the rate of ₹ 20 per litre and the cost of metal used, if its cost ₹ 10 per 100 cm^2 (pi = 3.14) .

A steel tape 1m long is correctly calibrated for a temperature of 27.0 ^@C . The length of a steel rod measured by this tape is found to be 63.0 cm on a hot day when the temperature is 45.0 ^@C . What is the actual length of the steel rod on that day? What Is the length of the same steel rod on a day when the temperature is 27.0 ^@C ? Coefficient of linear expansion of steel = 1.20xx10^-5 K^-1 .

A person cannot see objects nearer than 1.5 m from his eyes while a person with normal vision can see objects upto 25 cm from his eyes. What is the nature and power of the, lens required to correct this defect?

A 14.5 kg mass, fastened to the end of a steel wire of unstretched length 1.0 m, is whirled in a vertical circle with an angular velocity of 2 rev/s at the bottom of the circle. The cross-sectional area of the wire is 0.065 cm^2 . Calculate the elongation of the wire when the mass is at the lowest point of its path.

A uniform rope of length 12 m amd mass 6 kg hangs vertically from a rigid support.A block of mass 2 kg is attached to the free end of the rope.A transverse pulse of wave length 0.06m is produced at the lower end of the rope.What is the wavelength of the pulse when it reaches the top of the rope?

A compound microscope has an objective of focal length 1 cm, an eye piece of focal length 2.5 cm and a tube of length 15 cm. Find its magnification for normal adjustment.