761. What converts mechanical energy into electrical energy? 
Dynamo

762. Which type of lens is used in cameras? 
Convex lens

763. Which type of glass is used for making lenses? 
Flint glass

764. Which was the first organic compound prepared in a laboratory?
Urea 

765. The nuclear radiation first affects which organ of the human body? 
Brain 

766. Which metal has the highest melting point?
Tungsten 

767. Which is the most abundant element in the Moon? 
Oxygen 

768. Molisch test is used to detect the presence of. 
Carbohydrates

769. Which is the most abundant type of coal? 
Bituminous

770. Which halogen is used as an antiseptic? 
Iodine

771. Plaster of Paris is prepared by heating. 
Gypsum

772. Which element has the largest number of isotopes?
Tin 

773. Silver objects turn dark on prolonged exposure to air due to the formation of.
Silver sulphide 

774. Who discovered radiocarbon dating?
Willard Franck Libby 

775. Which sugar is found maximum in honey? 
Fructose 

776. Which disease is also known as ‘Bronchocele’i 
Goitre 

777. In the human body, the structure to which appendix is attached? 
Large intestine 

778. Which hormone regulates calcium & phosphate in a human body? 
Parathyroid hormone

779. Which is the smallest unit of an element that takes part in a chemical reaction? 
Electron

780. What is the period of revolution of a geostationary satellite?
24 hours 

781. Which type of mirror is used in the headlamp of cars? 
Parabolic concave 

782. The eustachian tube connects which parts of the body?
Ear&throat 

783. The number of molecules contained in one mole of a gas is called.
Avogadro number 

784. Which acid is usually present in the fizzy soft drinks? 
Carbonic acid

785. Which property of a star is indicated by its colour?
Temperature 

786. Which metal is used in the storage batteries? 
Lead 

787. Who invented the ultrasound scanning?
Ian Donald 

788. In the process of dialysis, used on kidney patients, the phenomenon involved is. 
Osmosis

789. Which is the longest key in a computer keyboard?
Space bar 

790. Which part of the brain controls the heartbeats? 
Medulla Oblongata

791. Which gas is used for the artificial ripening of fruits?
Ethylene 

792. Which organ of body purifies blood?
Kidney 

793. Which microorganisms cause the foot & mouth disease in animals?
Virus 

794. The radioactive disintegration of uranium ultimately leads to. 
Lead

795. Which gas is used in the welding industry?
Acetylene