3:4
5:4
5:1
3:2
A radioactive element emits an alpha particle. The mass number of the element, after emission
A radioactive substance does not undergo any change (in mass or charge) during
A radioactive substance has a half-life of 4 months. Three fourth of the substance would decay in
A ray of light travels from water to air. If the angle of incidence is 40°, then the angle of refraction is
A rear-view mirror for driving is
A remote control gadget (for TV etc.) has in it
A resonant system has a fundamental frequency of 100 Hz. If the next higher frequency that gives a resonance are 300 Hz and 500 Hz, the system could be
A rocket works on the principle of conservation of
A shell, initially at rest suddenly explodes into two equal fragments A and B. Which one of the following is observed?
A simple microscope consists of
