Q1: Drills are usually made of

ANS:B - high speed steel

Drills are usually made of high-speed steel (HSS). High-speed steel is a type of tool steel that is specifically designed for use in cutting tools, such as drills, taps, and milling cutters. It is renowned for its ability to maintain its hardness and cutting ability at elevated temperatures, allowing it to withstand the high speeds and temperatures generated during metal cutting operations. High-speed steel typically contains alloying elements such as tungsten, molybdenum, chromium, and vanadium, which enhance its hardness, toughness, and heat resistance. These properties make high-speed steel an ideal material for manufacturing drills, as it can efficiently cut through various metals and withstand the rigors of drilling operations. While other materials such as tungsten carbide and cermets are also used in some specialized drilling applications, high-speed steel remains the most common and versatile material for drill manufacturing due to its excellent balance of hardness, toughness, and cost-effectiveness.