X & Y ray has similarity in?

Identify the organ which has similarity in origin and structure is called-

Which ray has the same velocity as that of light-

A rotating ray makes an angle -5(1)/(12)pi . Determine the direction in which the ray has comletely rotated and there after what more angle it has produced.

ER has a structure similar to

Which one of the following has least similar characters ?

Which of the following compounds has similar odour as that of H_(2)O_(2) -

From the focus (-5,0) of the ellipse (x^(2))/(45)+(y^(2))/(20) =1 , a ray of light is sent which makes angle cos^(-1)((-1)/(sqrt(5))) with the positive direction of X-axis upon reacting the ellipse the ray is reflected from it. Slope of the reflected ray is

State whether the following statements are true or false : A ray has no end point.

Electromagnetic waves are emitted from an atom in excited state and gamma -rays are emitted during radioactive disintegration. What are the similarities and dissimilarities between them ?

Two acute angled traingle ABC and PQR are similar. Their circumcentres are X,Y respectively. If BC and QR are corresponding sides, then prove that BX: QY = BC:QR.