Railway GK Questions 2026

The bay narrows and shallows inland, so the incoming tidal wave is funnelled into a smaller and smaller cross-section and its height is greatly magnified, giving the greatest difference between high and low water anywhere on earth.

Spring tides occur at new moon and at full moon, when the sun, the earth and the moon lie in a straight line, a position called syzygy.

Textbooks describing the distribution of water on earth give about 97.2 per cent as ocean water, roughly 2 per cent locked in ice caps and glaciers, and well under 1 per cent as groundwater, lakes, rivers, soil moisture and water vapour together.

The Ring of Fire is a horseshoe-shaped belt running around the rim of the Pacific Ocean, from the Andes up the west coast of the Americas, across the Aleutians and down through Japan, the Philippines and Indonesia to New Zealand.

El Nino, Spanish for the child, is the warm surface water that appears off the coast of Peru and Ecuador around Christmas in some years, replacing the normally cold Peru or Humboldt current.

It is a warm current of the Indian Ocean that flows southward along the eastern coast of southern Africa, carrying tropical water towards the Cape before most of it turns back into the Indian Ocean.

The sensation of a sound persists in the human brain for roughly one tenth of a second, so a reflected sound must arrive at least that much after the original to be heard as a separate echo.

SONAR stands for Sound Navigation and Ranging. A transmitter on the ship sends short ultrasonic pulses into the water, the pulses are reflected from the sea bed, a submarine, an iceberg or a shoal of fish, and a detector records the returning echo.

Sound travels fastest in solids because their particles are packed closely and are strongly bound, so a disturbance is passed on to the next particle almost at once.

This is the band of frequencies to which a healthy human ear responds, and the upper limit falls with age.

A vacuum contains no particles, and a mechanical wave such as sound can travel only by making particles vibrate and hand the disturbance on to their neighbours.

In a sound wave the particles of the medium vibrate back and forth along the same line in which the wave is travelling, producing regions where they crowd together, called compressions, and regions where they spread apart, called rarefactions.

The flash and the clap are produced at the same instant by the same discharge.

Amplitude is the maximum displacement of a particle of the medium from its rest position, and the energy carried by a wave increases with the square of the amplitude.

Convert the units first: 1 kilohertz is 1000 hertz and 50 centimetres is 0.5 metre. The speed is frequency multiplied by wavelength, that is 1000 multiplied by 0.5, which gives 500 metres per second.

Pitch is the characteristic of a sound by which the brain judges it as shrill or flat, and it is decided by the frequency of the wave.

The speed of a wave is the product of its frequency and its wavelength, so the speed here is 50 hertz multiplied by 4 metres, that is 200 metres per second.

The Minamata Convention on Mercury was adopted in 2013 and entered into force in 2017. It controls the supply and trade of mercury, restricts its use in products such as batteries, switches and certain measuring devices, and regulates emissions from coal burning and from small-scale gold mining.

The Cartagena Protocol on Biosafety, adopted in 2000, governs the safe handling, transport and use of living modified organisms produced by modern biotechnology.

The United Nations Conference on the Human Environment met at Stockholm in June 1972 and was the first global gathering to treat the environment as a subject of international policy.