RRB ALP GK Questions 2026

All the potential energy at the top turns into kinetic energy at the mean position, so v = √(2gh) = √(2 × 10 × 0.20) = 2 m/s. When the bob is released from rest at height h, it has potential energy mgh and no kinetic energy.

A transformer raises or lowers an AC voltage using electromagnetic induction between two coils. A transformer has a primary and a secondary coil wound on a common soft-iron core.

Rotational kinetic energy is ½Iω², and the ring has the larger moment of inertia. For a thin ring about the axis through its centre and perpendicular to its plane, all the mass sits at distance R, so I = MR².

Using Q = mcΔT, the mass works out to 20,000 ÷ (400 × 10) = 5 kg. The heat needed to warm a body is Q = mcΔT, where m is the mass, c the specific heat capacity and ΔT the rise in temperature.

Power is the reciprocal of focal length in metres, and a concave lens has a negative focal length. The power of a lens is P = 1/f, with f in metres, and its unit is the dioptre (D).

The formula T₀ = 2π√(L/g) holds only for small swings; at large amplitudes the period grows.

On a level curve, friction alone supplies the centripetal force, so a cyclist slips when the needed force exceeds the maximum friction.

A compound microscope uses two convex lenses, and its magnification depends on the tube length. The objective is a convex lens of very short focal length that forms a real, enlarged image of the specimen.

A real, inverted image of the same size forms only when the object sits at twice the focal length of a convex lens, so 2f = 10 cm and f = 5 cm.

In this cell hydrogen is fed to the anode and oxidised, oxygen is fed to the cathode and reduced, and the two combine to give water, so the cell produces electricity for as long as the gases are supplied and leaves no polluting exhaust.

Galvanisation is the coating of iron or steel with zinc, usually by dipping the article in molten zinc, and it protects the iron twice over: the layer keeps out air and moisture, and because zinc is the more reactive metal it corrodes in place of the iron even where the…

Pure alumina melts at a very high temperature, so it is dissolved in molten cryolite, which is sodium aluminium fluoride, usually with a little fluorspar added; this brings the working temperature down sharply and makes the melt a good conductor.

The lead-acid cell has a spongy lead negative plate and a lead dioxide positive plate dipped in dilute sulphuric acid, and as the cell discharges both plates turn to lead sulphate while the acid becomes weaker, which is why its state of charge can be judged from the specific gravity…

In the Leclanche dry cell the outer container itself is made of zinc and acts as the anode, being oxidised to zinc ions as the cell works, which is why an old cell often leaks when the container is eaten through.

Its reaction is reversible, so passing a current through it in the opposite direction converts the products back into lead and lead dioxide and the cell can be used again; such a cell is called a secondary or storage cell, and the car battery is the common example.

In the chlor-alkali process a concentrated solution of sodium chloride is electrolysed; chloride ions are oxidised at the anode and come off as chlorine gas, hydrogen is set free at the cathode, and sodium hydroxide remains in the solution, which is why the industry yields three useful products at once.

The metal ions in the plating bath carry a positive charge, so they move towards the negative electrode and are reduced to metal there; the article must therefore be the cathode for the coating to build up on it.

One faraday is the charge carried by one mole of electrons, obtained by multiplying the charge on a single electron by the Avogadro number, and it comes to about 96,500 coulombs; passing one faraday through an electrolyte liberates one gram equivalent of the substance at an electrode.

The anode is the electrode joined to the positive terminal of the supply, so negatively charged ions, the anions, travel to it and give up electrons there; loss of electrons is oxidation.

When cells are joined in parallel all their positive terminals are connected together and all their negative terminals together, so each cell is across the same two points and the voltage of the combination is the voltage of one cell, that is 12 volts.