SSC GK Questions 2026

Coal is a sedimentary rock formed from buried plant matter, and prolonged heat and pressure drive off its volatile content and rearrange the carbon, first into harder anthracite and finally into graphite, a metamorphic rock of nearly pure carbon.

It lies in the upper mantle just below the rigid outer shell, is weak and partly molten, and is the main source of the magma that reaches the surface through volcanoes; the plates slide over it.

The core bends P waves sharply and stops S waves altogether, so a belt of the Earth surface receives neither type of wave from a given earthquake.

Granite forms when magma cools slowly deep below the surface, which gives the crystals time to grow, so the rock is coarse and speckled.

It marks the change from the molten outer core to the solid inner core, and is named after Inge Lehmann, who deduced from the behaviour of earthquake waves that the innermost part of the planet is solid.

Almost half the weight of the crust, about 46.6 per cent, is oxygen, because it is locked into the silicate minerals of which nearly all crustal rocks are made rather than existing as free gas.

They are built up layer by layer as sediment settles over the remains of living things and hardens gently, so shells, bones and plant matter survive as fossils.

The Deccan Trap was formed by vast fissure eruptions in which lava spread over the surface and cooled quickly, giving a fine-grained extrusive igneous rock, basalt.

Limestone is a sedimentary rock made largely of calcium carbonate, and when heat and pressure recrystallise it without melting it, the result is marble, the stone used in the Taj Mahal and in the Dilwara temples.

They are transverse waves, in which particles vibrate at right angles to the direction of travel, and such motion cannot be sustained in a fluid, so S waves die out at the outer core.

Named after the Croatian seismologist who noticed that earthquake waves suddenly speed up at a certain depth, it marks the base of the crust and the top of the mantle, and is commonly shortened to the Moho.

The erg is the unit of work in the CGS system, being one dyne of force acting through one centimetre, and since one newton is one lakh dyne and one metre is a hundred centimetre, one joule works out to ten million erg, that is 10 raised to the power…

A stone at rest at a height has no motion and therefore no kinetic energy, but it possesses gravitational potential energy equal to its mass into the acceleration due to gravity into the height of the tower.

The force he applies to support the load acts vertically upward, while his displacement along the platform is horizontal, so the angle between force and displacement is ninety degrees and the work done against gravity is zero, however tired he may feel.

The work-energy theorem states that the net work done on a body equals the difference between its final and initial kinetic energies, which is why a push that speeds a body up does positive work while friction, which slows it, does negative work.

A dynamo, also called a generator, is turned by some mechanical agency such as falling water, steam or a bicycle wheel, and the rotation of a coil in a magnetic field produces an electric current by electromagnetic induction.

Kinetic energy is half the mass into the square of the speed, so when the speed is multiplied by two the energy is multiplied by two squared, that is four.

Household electricity is billed in these units, and one kilowatt hour, popularly called one unit, is the energy consumed when an appliance of one kilowatt runs for one hour; in SI terms it equals 3.6 million joule.

The horsepower is an older unit of power that survives in the rating of motors and vehicles, and one horsepower is taken as about 746 watt, that is roughly three quarters of a kilowatt.

Power is the rate of doing work, that is work divided by the time taken, so its unit is the joule per second, which is named the watt after James Watt.