621. Which chemically inactive gases are usually filled in bulbs to prolong the life of filament?
Nitrogen & Argon
622. What is the SI unit of electric power?
623. What is the name of the device that reverses the direction of flow of current through a circuit?
624. Which instrument can detect the presence of a current in a circuit?
625. In India, what is the frequency of Alternating Current (AC)?
626. What is the potential difference of AC supplied in India?
627. A generator converts ———- energy into electrical energy?
628. What is the working principle of a generator?
629. In hydroelectric power plants, which energy of water is converted into electrical energy?
630. The greater the percentage of————– in a fuel, the greater is its calorific value.
631. The process of burning of material in the absence of oxygen is known as ———–
632. Which chemical is produced through the Solvency process or ammonia-soda process?
633. Which colour is showed by a universal indicator in a solution with neutral pH value?
634. Ponds look shallow due to the ——— of light.
635. Which metal alloy is used to make permanent magnets?
636. The force of attraction which stick the water particles at the window glass is ————-
637. What is the process in which two light nuclei to form a heavier nucleus with the release of energy?
638. What is the working principle of an atomic bomb?
639. What will be the weight of a body at the centre of Earth?
640. What is the power of an ordinary torch cell?
641. Which colour is seen on the outer edge of a rainbow?
642. Which device is used for detecting even feeble current?
643. Which is the strongest force in nature?
644. Which rays of the sunlight makes solar cooker hot?
645. The capillary action phenomenon of water rising up a narrow tube dipped in water is due to
646. The image formed by a plane mirror is ……….
647. Which kind of cells converts light energy to electric energy?
648. Muddy water is an example of a solution.
649. Which rays of sunlight is absorbed by carbon dioxide molecules in the atmosphere?
650. Which type of waves a cellular phone uses to operate?
651. Bats can understand obstacles because they produce ————-
Ultrasonic sound waves
652. Which process is used to separate water & alcohol?
653. Which was the first planet founded by Mathematical prediction rather than by empirical observation?
654. Liquefied natural gas or LNG is natural gas, predominantly composed of?
655. The mineral form of which chemical is known as Sassolite?