Question 551 Which one of the following is not radioactive? A) Astanine B) Francium C) Tritium D) Zirconium No Details
Question 553 Which of the following has highest frequency? A) Cosmic rays B) x rays C) Radio waves D) Micro waves No Details
Question 554 An element X forms an oxide XO3 What is the valency of X? A) 1 B) 2 C) 3 D) 6 No Details
Question 557 The father of modern chemistry is? A) Priestley B) Lavoisier C) Dalton D) Mendeleeff No Details
Question 558 What was the fissionable material used in the bombs dropped at Nagasaki (Japan) in the years 1945? A) Sodium B) Plutonium C) Potassium D) Uranium No Details
Question 559 In nuclear raeactors the speed of neutrons is slowed down by ? A) heavy water B) ordinary water C) zinc rods D) moten caustic soda No Details
Question 560 Hydrogen bomb is based on the principle of ? A) nuclear fission B) nuclear fusion C) natural radioactivity D) artificial radioactivity No Details