Nuclei — Physics STD 12 Science — Question

A parallel plate condenser has a capacitance 50μF in air and 110μF when immersed in an oil. The dielectric constant ‘k’ of the oil is

Radius of central zone of circular zone plate is 2.3 mm. Wavelength of incident light is 5893.  Source is at a distance of 6m  Then the distance of first image will be

In the above question, potential difference across the 40Ω resistance will be

If the amplification factor of a triode (m) is 22 and its plate resistance is 6600 ohm, then the mutual conductance of this valve is mho is

A point object O is placed on the principal axis of a convex lens of focal length 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. If the eye is placed 60 cm to the right of the lens at a distance h below the principal axis, then the maximum value of h to see the image will be

1. Must be longitudinal
2. May be longitudinal
3. Must be transverse
4. May be transverse.

The temperature at which thermal electric power of a thermo couple becomes zero is called

In the adjoining circuit, the battery  has an e.m.f of 12 volt and zero internal resistance while the battery E has an e.m.f  of 2 volt. If the galvanometer G reads zero, then the value of the resistance X in ohm is

Consider four circuits shown in the figure below. In which circuit power dissipated is greatest  (Neglect the internal resistance of the power supply)

If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the lines of force, what will happen to proton and electron