Question

12)Which one of the following is an exothermic process? A) ice melting B) water evaporating C) boiling soup D) condensation of water vapor E) Ammonium thiocyanate and barium hydroxide are mixed at 25 °C: the temperature drops. 13)Which one of the following is correct? A) V + 2. c B) v + 1-C C) v = ch D) 2 = c v E) v = c 14) The photoelectric effect is A) the total reflection of light by metals giving them their typical luster B) the production of current by silicon solar cells when exposed to sunlight C) the ejection of electrons by a metal when struck with light of sufficient energy D) the darkening of photographic film when exposed to an electric field E) a relativistic effect 15)Of the following transitions in the Bohr hydrogen atom, the transition results in the emission of the lowest-energy photon. A) n=1 = 6 B) n= 6 – n=1 C) n=6 n =3 D) n = 3 = 6 E) n=1 →n=4 16 The ground state electron configuration of Ga is A) 1s22s23s23p64s23d104p1 B) 1s22s22p63s23p64524d104p1 C) 1s22s22p63s23p64s23d104p1 D) 1s22s22p63s23p64s23d104d1 E) [Ar]4s23d11

Answer 1

Ans: Dedy Condensation of water vapour is exothermic because in this process water molecules Come closer and log energy in form of heat 13 E) Plank equation E= ho=he v=0 (c=07) 14).The photo electtic effect is the ejection of electron by a metal when struck with light of sufficient energy hon Te Photoel betric effect. Site Phoelectric metal surface 15) Emission of photon occur when eleet om from higher energy level to lower energy level moves. n=6 - n-3 electron transition correspond to lowest energy emission in given case. Ansic) 16): Ga : Grond state Configuration c) 15, 252pgs'sp® 4s? 3d!" opt Scanned with CamScanner