ANS:C - Mechanic

Explanation: All except Mechanic help in building a house.

ANS:C - in parallel with the circuit

Voltage (Electrical potential) is an electrical force applied to move a charge from one point (A) to another point (B). ie) Work done (Joules). At point A high is available and in moving the charge to point B as work is done some potential is consumed. Hence potential at B will be less than at A. Hence a potential difference between points A &B. A voltmeter is used to measure the potential difference between two points. Any measurement of difference is wrt to a reference point. Hence, a voltmeter is connected across (Parallel) two points.

ANS:D - Glazed ware.

1. R.C.C. (Reinforced Concrete Cement):
   • R.C.C. pipes and structures are commonly used in sewage systems due to their durability, strength, and relatively low cost. However, they are susceptible to hydrogen sulfide (H2S) corrosion under certain conditions.
   • Hydrogen sulfide gas is often present in sewage due to the decomposition of organic matter by anaerobic bacteria. When hydrogen sulfide comes into contact with moisture and oxygen, it can form sulfuric acid (H2SO4), which is highly corrosive to concrete.
   • The acid attack on concrete can lead to the deterioration of the cement matrix and the corrosion of embedded steel reinforcement, compromising the structural integrity of R.C.C. pipes and structures over time.
   • While measures such as using high-quality concrete mixes, applying protective coatings, and implementing corrosion-resistant reinforcement can help mitigate hydrogen sulfide corrosion in R.C.C. structures, they are not completely immune to this type of corrosion.
2. Glazed Stone Wares:
   • Glazed stone ware pipes are made from clay and coated with a layer of glaze, which provides a smooth and impermeable surface. This glaze layer acts as a barrier that prevents hydrogen sulfide gas from directly contacting the underlying clay material.
   • The impermeable glaze coating also helps to resist chemical attack and corrosion, including hydrogen sulfide corrosion. By reducing the exposure of the underlying clay material to corrosive agents, glazed stone ware pipes exhibit greater resistance to corrosion compared to unglazed stone ware or other porous materials.
   • Glazed stone ware pipes are commonly used in sewage systems, particularly in areas where hydrogen sulfide corrosion is a concern, due to their durability and resistance to chemical attack.
3. Asbestos Cement:
   • Asbestos cement pipes are composed of a mixture of asbestos fibers and cement, which are combined to form a durable and lightweight material. These pipes have been widely used for sewerage and drainage systems due to their corrosion resistance, low cost, and ease of installation.
   • Asbestos cement pipes are generally resistant to hydrogen sulfide corrosion. The cement matrix provides a protective barrier against chemical attack, while the asbestos fibers add strength and durability to the material.
   • However, it's important to note that asbestos cement pipes may still be susceptible to other forms of degradation over time, such as physical wear and tear, mechanical damage, and environmental factors.
4. Glazed Ware:
   • Glazed ware, which typically refers to ceramic or porcelain materials coated with a layer of glaze, is commonly used in various applications including sanitary ware, tiles, and decorative items.
   • Similar to glazed stone ware pipes, glazed ware products benefit from the impermeable and chemically resistant properties of the glaze coating. The glaze acts as a protective barrier that prevents the underlying ceramic material from being exposed to corrosive agents such as hydrogen sulfide gas.
   • While glazed ware products may not be specifically designed for sewage system applications, their resistance to chemical attack makes them suitable for use in environments where corrosion is a concern.

ANS:A - 0.375 V

No. of comparators = 2ⁿ - 1 = 2⁴ - 1 = 15 .