ANS:E - Both I and II are implicit

Explanation: The 'thorough' overhauling is needed only in case of an obsolete system. So, I is implicit. Overhauling is done for improvement. So, II is also implicit.

ANS:A - 8 4 16 12 20

No answer description is available. Let's discuss.

ANS:B - momentum

Moment = force x Perpendicular distance.

Momentum = mass x velocity.

ANS:A - 0.0

No answer description is available.

ANS:C - fine grinding

A ball mill is primarily used for fine grinding.

Explanation:

• Ball Mill: A ball mill is a cylindrical device used in grinding (or mixing) materials like ores, chemicals, ceramic raw materials, and paints. It operates by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground.
• Purpose:
  • Crushing: Ball mills are not typically used for primary crushing but rather for refining crushed materials.
  • Coarse Grinding: Although ball mills can handle larger feed sizes, their primary function is not coarse grinding but rather fine grinding.
  • Fine Grinding: Ball mills are widely used for fine grinding of materials. They are efficient in grinding down to very small particle sizes, typically in the micron or sub-micron range.
  • Attrition: While some attrition may occur due to the tumbling action of the grinding media (balls) inside the mill, ball mills are not specifically designed for attrition.
• Applications:
  • Ball mills are commonly used in mineral processing, cement, ceramics, and chemical industries for fine grinding applications where particle size reduction and homogenization of materials are required.

ANS:A - Mcloid

A pressure of 0.0001 absolute psi is extremely low and falls within the range typically measurable by a McLeod gauge.

Explanation:

• McLeod Gauge:
  • A McLeod gauge is a specialized instrument used to measure very low pressures, typically in the range of 10^-6 to 10^-3 absolute atmospheres, which corresponds roughly to 10^-4 to 10^-1 absolute psi.
  • It operates on the principle of compressing a known volume of gas and measuring the pressure change, allowing for highly sensitive pressure measurements.
• Other Gauges:
  • Pirani Gauge: A Pirani gauge measures pressures in the low to medium vacuum range (typically around 10^-3 to 10^3 Torr, or about 10^-3 to 10^3 mbar), but not as low as a McLeod gauge.
  • Thermocouple Gauge: Also known as a thermocouple vacuum gauge, it measures pressures from low to high vacuum (typically around 10^-3 to 10^-10 Torr), but is not suitable for measuring pressures as low as 0.0001 absolute psi.
• Conclusion:
  • Since a pressure of 0.0001 absolute psi is extremely low and falls within the sensitivity range of a McLeod gauge, it is the most appropriate instrument for measuring such low pressures. Therefore, the correct answer is McLeod gauge.

ANS:A - Ukraine

The US announced military assistance worth over USD 3.75 billion for Ukraine and its European allies.

ANS:A - India

India's real GDP is expected to grow 7% in 2022-23, according to the First Advance Estimates of National Income released by the National Statistical Office (NSO).

ANS:C - India

India's first underwater metro will start by December 2023.

ANS:A - Sudan

India deployed a platoon of women peacekeepers to the UN Mission in Sudan.