polarisation
reflection
refraction
diffraction
A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of the emfs is
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?
