List conditions under which combustion can take place.

(c) When object is placed between the focus and centre of curvature

The correct conditions is q = 0. So option (iii) is correct.

Longitudinal waves

(c) Low temperature, high pressure

Changes at puberty:   Sudden increase in height.   Broadening of shoulders and widening of chest in boys. In girls, the region below waist becomes wider.   At puberty, the voice box or...

Substances that are stronger oxidising agents than ferrous ions can oxidise ferrous ions. Fe2+ → Fe3+ + e-1  ;   Eø =  - 0.77 V This implies that the substances having higher reduction potentials than +0.77 V can...

No, double displacement reaction takes place when there is a formation of a slightly soluble salt.

(c) for both longitudinal and transverse waves EXPLANATION:  The phenomenon of beats can take place for both longitudinal and transverse waves only conditions to be followed is the difference in the frequencies...

(b) light goes from optically denser medium to rarer medium EXPLANATION:  When the light goes from a denser medium to lighter medium, it goes away from the normal. When the angle of...

(b) According to Snell’s Law,  sin i/ sin r =μ 2/μ 1 = where r = 90º for particular incidence angle called critical angle. When the incidence angle is equal to or greater than...