A) When a high velocity beam of electrons strikes a metal surface B) When light rays fall on the metal surface C) When metals are subjected to strong magnetic fields D) When temperature of metals is raised to a level above the crystallization temperature. Ans : (A)
A) Polythene B) Mica C) Paper oiled D) Empire cloth. Ans : (B)
A) is independent of temperature B) increases with increasing temperature C) depends primarily on the method of heating D) decreases with increasing temperature. Ans : (D)
A) addition polymerization B) condensation C) condensation polymerization D) copolymerization of ethylene monomers. Ans : (A)
A) (0 1 0) B) (0 0 1) C) (1 0 0) D) (1 1 1). Ans : (C)
A) Vander Waals B) ionic C) covalent D) a mixture of covalent and Vander Waals. Ans : (A)
A) elastomer B) plastic C) dilatant D) copolymer. Ans : (A)
A) compare the extent of purity of semi-conductor materials B) measured the extent of doping of intrinsic semiconductors C) compare the efficiency of thermoelectric, materials. Ans : (C)
A) an alky1 halide B) a hydrocarbon C) an alcohol D) an ester. Ans : (B)
A) pressure sensitive elements B) electrodes of thermionic valves C) bulb filaments D) automatic voltage regulators. Ans : (B)