A parallel plate capacitor filled with a medium of dielectric constant 10, is connected across a battery and is charged. The dielectric slab is replaced by another slab of dielectric constant 15. Then the energy of capacitor will :

A positive charge particle of 100 mg is thrown in opposite direction to a uniform electric field of strength 1 $$\times$$ 10⁵ NC^$$-$$1. If the charge on the particle is 40 $$\mu$$C and the initial velocity is 200 ms^$$-$$1, how much distance it will travel before coming to the rest momentarily :

Using Young's double slit experiment, a monochromatic light of wavelength 5000 $$\mathop A\limits^o $$ produces fringes of fringe width 0.5 mm. If another monochromatic light of wavelength 6000 $$\mathop A\limits^o $$ is used and the separation between the slits is doubled, then the new fringe width will be :

Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission :