Periodic Classification of Elements — Science STD 10 — Question

The radii of curvature of two surfaces of a double convex lens are 10 cm each. Calculate its focal length and power of the lens in air and liquid. Refractive indices of glass and liquid are 1.5 and 1.8 respectively.

How will you enhance the rate of decomposition of potassium chlorate?

The optical prescription of a pair of spectacle is
Right eye: -3.5 D, Left eye: -4.00 D.
(i) Name the defect of the eye.

If the volume of a metallic block increases by 0.12% when it is heated through 20°C, what is the coefficient of cubical expansion.

What is the chemical reaction taken place in the tarnishing of silver anklet?

A compound made up of two elements A and B has A = 70%, B = 30%. Their relative number of moles in the compound are 1.25 and 1.88. Calculate.
(a) Atomic masses of the elements A and B.
(b) The molecular formula of the compound, if its molecular mass is found to be 160.

Write down the medical and industrial application of radioisotopes?

Why toothpaste are basic in nature?

If the volume of a block of metal changes by 12% when it is heated by 30°C. What is the coefficient of linear expansion, superficial expansion?

Write short notes on
(i) Astronomical telescope
(ii) Terrestrial telescope.