The statement “Silver Revolution refers to increased pulse production” is incorrect. The Silver Revolution actually refers to the rapid increase in egg and poultry production in India during the 1980s, which boosted nutrition and rural income.

• White Revolution: Increased milk production under Dr. Verghese Kurien.
• Green Revolution: Rise in food grain output (wheat, rice) using high-yield varieties.
• Yellow Revolution: Boosted oilseed production for self-sufficiency in edible oils.

Explanation: The S.I. unit of electric current is the Ampere (A). It is defined as the rate of flow of electric charge through a conductor. One ampere equals one coulomb of charge passing through a point in one second.

Explanation: The terms Dolby B and Dolby C refer to noise reduction circuits used in tape recorders and sound systems. These technologies reduce background hiss and unwanted noise during playback and recording, thereby improving the overall sound quality.

Explanation: Electrons are negatively charged particles that revolve around the nucleus in fixed paths called orbits or shells. The nucleus contains positively charged protons and neutral neutrons, and most of the atom’s mass is concentrated in the nucleus.

Sound becomes hazardous and causes noise pollution when its intensity exceeds 80 decibels (dB). Prolonged exposure to such high noise levels can lead to hearing loss, stress, sleep disturbances, and other health problems. Common sources include heavy traffic, loudspeakers, machinery, and construction activities. Sounds above 120 dB can cause immediate ear damage or pain.

Other options (for context)

• Above 50 dB: Considered moderate — typical of normal conversation or office noise.
• Above 100 dB: Very loud and potentially painful, but 80 dB is the threshold for long-term hazard.
• Above 130 dB: Extremely loud, causes immediate physical pain and ear damage.

The Abacus is considered the first calculating device in human history. It was invented around 2500 BCE and used in ancient civilizations such as China, Egypt, and Mesopotamia. The Abacus consists of beads that slide on rods or wires, representing numbers, and is used to perform basic arithmetic operations like addition, subtraction, multiplication, and division. It laid the foundation for modern computing and calculating tools.

Other options (for context)

• Calculator: A modern electronic device for computation, developed much later.
• Turing machine: A theoretical computational model proposed by Alan Turing in 1936.
• Pascaline: A mechanical calculator invented by Blaise Pascal in 1642, long after the Abacus.

Explanation: Ampicillin is a semi-synthetic derivative of penicillin and belongs to the β-lactam group of antibiotics. It inhibits bacterial cell wall synthesis and is effective against a wide range of gram-positive and gram-negative bacteria. Therefore, it is classified as a broad-spectrum antibiotic. Paracetamol is not an antibiotic, and penicillin is a narrow-spectrum antibiotic.