The species that has the same number of electrons as ³⁵₁₇Cl is 

A. ³²₁₆S 

B. ³⁴₁₆S⁺ 

C. ⁴⁰₁₈Ar⁺ 

D. ³⁵₁₆S²⁻ 

The majority charge carriers in a p-type semiconductor are 

A. free electrons 

B. conduction electrons 

C. ions 

D. holes

The principle use of hydrofluoric acid is 

A. in etching glass 

B. as a bleaching agent 

C. as an extremely strong oxidizing agent 

D. in the preparation of strong organic fluorine compounds

The ionization energy of hydrogen atom in the ground state is 

A. 13 .6 MeV  

B. 13 .6 eV  

C. 13 .6 Joule 

D. Zero

Which compound, when dissolved in water, conducts electricity and forms a basic solution? 

A. HCl 

B. CH₃COOH 

C. CH₃OH 

D. NaOH

Golden rice is a genetically-modified crop plant where the incorporated gene is meant for biosynthesis of

A. Omega-3 fatty acids

B. Vitamin A

C. Vitamin B

D. Vitamin C

An object moves m a circular path with a constant speed. Which one of the following statements is correct? 

A. The centripetal acceleration of the “object is smaller for a gentle curve (i.e.,curve of larger radius) than that for a sharp curve (i .e ., curve of smaller radius). 

B. The centripetal accel eration is greater for a gentle curve than that for a sharp curve. 

C. The centripetal acceleration is the same for both, the gentle and sharp curves. 

D. The centripetal acceleration causes the object to slow down.

When pure water boils vigorously, the bubbles that rise to the surface are composed primarily of 

A. air 

B. hydrogen 

C. hydrogen and oxygen 

D. water vapour

If some object is weighed when submerged in water, what will happen to its weight in air ? 

A. Increase 

B. Decrease 

C. Remain exactly the same 

D. Increase or decrease cannot be predicted

Water boils at a lower temperature at high altitudes, because 

A. the aur pressure is less 

B. outside temperature is less 

C. latent heat is less 

D. None of the above