A door is pushed, at a point whose distance from the hinges is 90 cm, with a force of 40 N. Calculate the moment of the force about the hinges.

A beam of light passing through a diverging lens of focal length 0.3m appear to be focused at a distance 0.2m behind the lens. Find the position of the object.

Keeping the temperature as constant, a gas is compressed four times of its initial pressure. The volume of gas in the container changing from 20cc (V₁ cc) to V₂ cc. Find the final volume V₂.

In the circuit diagram given below, three resistors R₁, R₂ and R₃ of 5 Ω, 10 Ω and 20 Ω respectively are connected as shown. Calculate:

A) Current through each resistor
B) Total current in the circuit
C) Total resistance in the circuit

A source producing a sound of frequency 90 Hz is approaching a stationary listener with a speed equal to (1/10) of the speed of sound. What will be the frequency heard by the listener?

A source of sound is moving with a velocity of 50 m s^–1 towards a stationary listener. The listener measures the frequency of the source as 1000 Hz. what will be the apparent frequency of the source when it is moving away from the listener after crossing him? (velocity of sound in the medium is 330 m s^–1)

A radon specimen emits radiation of 3.7 × 10³ GBq per second. Convert this disintegration in terms of curie. (one curie = 3.7 × 10¹⁰ disintegration per second).

Calculation of mass from mole
Calculate the mass of the following
i) 0.3 mole of aluminium (Atomic mass of Al = 27)
ii) 2.24 litre of SO₂ gas at S.T.P
iii) 1.51 × 10²³ molecules of water
iv) 5 × 10²³ molecules of glucose

Calculate the percentage of sulphur in H₂SO₄.

Find the mass of potassium chloride would be needed to form a saturated solution in 60 g of water at 303 K? Given that solubility of the KCl is 37 / 100 g at this temperature.

A solution was prepared by dissolving 25 g of sugar in 100 g of water. Calculate the mass percentage of solute.

Find the amount of urea which is to be dissolved in water to get 500 g of 10 % w / w aqueous solution?

What would be the pH of an aqueous solution of sulphuric acid which is 5 × 10^–5 mol litre^–1 in concentration.

If the pH of a solution is 4.5, what is its pOH?

What is the pH of 1.0 × 10^_–5 molar solution of KOH?