say two particles are moving with velocity of light  in opp direction then there relative velocity is ?

299792458 m/s

becoz in this case the particles will behave as light and

the speed of light is a constant from any frame of referrence (using EINSTEIN's theory of relativity)

CORRECT ME IF I AM WRONG

protyush u are very much right and ur value  299792458 is very acurate also

since speed =c.....

so simple relations wont work

by lorentz transformations

u^'_x=(u_x-v)/(1-v.u_x/c^2)

=(c-(-c)/1+1=c......i.e speed of lyt.............i don think its in jee syll