Explanation: 1 Gigabyte (GB) is equal to 1024 Megabytes (MB). Computer memory and storage are measured in powers of 2 (binary system), where 1 KB = 1024 bytes, 1 MB = 1024 KB, and 1 GB = 1024 MB.

The Widal test is used to diagnose Typhoid fever, a bacterial infection caused by Salmonella typhi. The test detects the presence of agglutinating antibodies (O and H) in a patient’s serum against the antigens of the typhoid bacteria. It helps confirm infection during the second week of illness.

• Cholera: Diagnosed by stool culture for Vibrio cholerae.
• Tuberculosis: Detected using sputum test or Mantoux test.
• AIDS: Diagnosed through ELISA or Western blot test for HIV.

Explanation: Sodium hydroxide (NaOH) is a base, so it does not turn blue litmus paper red. Instead, it turns red litmus paper blue. In contrast, lemon juice, acetic acid, and hydrochloric acid are acidic and turn blue litmus red.

Explanation: Kala-azar, also known as visceral leishmaniasis, is caused by the protozoan parasite Leishmania donovani. It is transmitted through the bite of the female Phlebotomus sandfly. The disease primarily affects the liver, spleen, and bone marrow, leading to symptoms such as fever, anemia, weight loss, and darkening of the skin. The term “Kala-azar” literally means “black fever.”

Explanation: The longest day in the Southern Hemisphere occurs on 22nd December, which marks the Summer Solstice in that hemisphere. On this date, the South Pole is tilted toward the Sun, resulting in longer daylight hours and shorter nights. Conversely, at the same time, the Northern Hemisphere experiences its winter solstice—the shortest day and longest night of the year. After 22nd December, the days in the Southern Hemisphere gradually begin to shorten.

Explanation: Carpal bones are the eight small bones that make up the wrist (also known as the carpus) in the human skeletal system. These bones are arranged in two rows — a proximal row (closer to the forearm) and a distal row (closer to the hand). They connect the bones of the forearm (radius and ulna) to the bones of the hand (metacarpals) and allow for the flexibility and movement of the wrist. The carpals are essential for various hand motions like bending, rotation, and gripping.

Explanation: The time period of a simple pendulum is given by the formula T = 2π√(L/g), where L is the length of the pendulum and g is the acceleration due to gravity. Since the Moon’s gravity is about 1/6th of Earth’s, the value of g decreases, causing the time period to increase.