Choose the correct option.

1. Which of the following circular rods (given radius r and length l) each made of the same material and whose ends are maintained at he same temperature will conduct most heat?
   

   1.   ?    r = ro; l = lo
   2.   ?    r = 2ro; l = lo
   3.   ?    r = ro; l = 2lo
   4.   ?    r = 2ro; l = 2lo

2. A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that is in plane of the coil. If due to a current i in the triangle a torque t acts on it, the side l of the triangle is:
   
   
   

   1.   ?    
   2.   ?    
   3.   ?    
   4.   ?    

3. The total energy of an electron in the first excited state of hydrogen atom is about - 3.4 eV. Its kinetic energy in this state is:

   1.   ?    3.4 eV
   2.   ?    6.8 eV
   3.   ?    -3.4 eV
   4.   ?    -6.8 eV

4. Identify the correctly matched pair:
   
   

   1.   ?    Basal convention – Biodiversity Conservation
   2.   ?    Kyoto Protocol – Climatic change
   3.   ?    Montreal Protocol – Global warming
   4.   ?    Ramsar Convention – Ground water pollution