Explanation

Introducing a shear angle on the cutting tool reduces resistance and spreads the cutting force over a smaller area.

This decreases the required cutting force and improves tool efficiency.

Shear angle is the key factor in reducing cutting force.

Explanation

Hot working is done above the recrystallisation temperature to make metals ductile and easily deformable.

It reduces internal stresses and prevents cracking during shaping.

Hot working must be above recrystallisation temperature for effective deformation.

Explanation

Chromite bricks are highly resistant to both acidic and basic slags, making them ideal for lining furnaces in metallurgical industries.

They can withstand high temperatures and chemical attack during metal processing.

Their high thermal conductivity also helps in efficient heat transfer in industrial furnaces.

Explanation

Tungsten is the strongest metal on Earth.

The melting point of Tungsten is ~ 3,422 °C.

The boiling point of Tungsten is ~ 5,555 °C.

Explanation

Chloro-fluoro carbon (CFC) refrigerants react with and destroy the ozone layer, which protects Earth from harmful UV radiation.

This depletion leads to increased UV exposure, causing health and environmental hazards.

CFCs have been largely replaced by HFCs and other eco-friendly refrigerants to reduce ozone damage.

Explanation

Brazing works best on copper because it has excellent thermal conductivity and wets well with filler metals.

Copper does not form a difficult oxide layer during brazing, ensuring a strong joint.

Copper and its alloys are most commonly brazed materials in plumbing and electrical work.

Explanation

In synthetic sand, water acts as the binder when mixed with silica sand and clay.

It helps provide plasticity and strength to the mould.

The amount of water must be carefully controlled to avoid defects in casting.

Explanation

Electrolytes are substances that dissociate into ions in molten or dissolved state and allow electric current to pass through.

Explanation

The ozone layer is a region within the stratosphere, extending from about 15 to 30 km (9 to 19 miles) above the Earth's surface.

It contains a high concentration of ozone (O3), a molecule made up of three oxygen atoms. 

The ozone layer plays a crucial role in protecting the Earth from harmful ultraviolet (UV) radiation from the sun, particularly UV-C and UV-B rays.

Explanation

 chemical formula for the ammonium ion is NH₄⁺ — a positively charged polyatomic ion formed from ammonia (NH₃) by the addition of a hydrogen ion (H⁺).