Tag: science & technology

Halogens (Group 17 elements) have 7 electrons in their outermost shell. This is one electron short of a stable octet, explaining their high reactivity. Fluorine, chlorine, bromine, and iodine all follow this pattern.

Blood group AB individuals have both A and B antigens on their RBCs, so they don't produce anti-A or anti-B antibodies. This makes them universal recipients. Option A correctly states this, though they can receive from A, B, AB, and O donors, not just A and B.

To find the bending load on a gear tooth: Power = 2 KW, Speed = 1000 RPM, PCD = 200 mm. First, calculate torque: Torque = Power / Angular velocity. Angular velocity = (2π × RPM) / 60 = (2π × 1000) / 60 = 100π/3 rad/s. Torque = 2000 W / (100π/3) = 60/π Nm. Tangential force (bending load) = Torque / radius = (60/π) / 0.1 = 600/π N. The answer is 600/π, which matches option C.

SSL (Secure Sockets Layer) is a standard security technology for establishing an encrypted link between a server and a client. The link ensures that all data passed between the web server and browser remains private and integral.

A botnet is a network of compromised computers (zombies) controlled by a malicious actor without the owners' knowledge. The term combines 'robot' and 'network' - these machines are used to send spam, launch DDoS attacks, or other malicious activities.

Compounds form through chemical bonding, which includes all three mechanisms: some elements lose electrons (ionic bonding), some gain electrons (ionic bonding), and some share electrons (covalent bonding). 'All of these' correctly captures that compounds can form via any of these processes.

Ozone (O3) in the stratosphere absorbs UV radiation and traps heat in the atmosphere, making it a greenhouse gas. While CO2 is the most abundant greenhouse gas, the question specifically asks for 'a' heat-trapping gas, and O3 is correct.

The pelagic zone is the open ocean area away from the shore and sea floor, essentially the 'open sea'. It has nothing to do with pelvic anatomy (pelvic girdle), polar regions, or African plains.

Stars are primarily composed of hydrogen (about 74% by mass) and helium (about 24%) through nuclear fusion. While oxygen exists in stars, it's not one of the two primary components.