Electric Charges and Fields — Physics STD 12 Science — Question

In a Young's double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case:

A capacitor is connected to a cell of emf E having some internal resistance r. The potential difference across the

(a) Cell is < E

(b) Cell is E

(c) Capacitor is > E

(d) Capacitor is < E

The peak voltage in a 220V AC source is:

A conducting wire is moving towards right in a magnetic field B. The direction of induced current in the wire is shown in the figure. The direction of magnetic field will be

(a) In the plane of paper pointing towards right

(b) In the plane of paper pointing towards left

(c) Perpendicular to the plane of paper and down‑wards

(d) Perpendicular to the plane of paper and upwards

Three plates of common surface area A are connected as shown. The effective capacitance will be

(a)

(b)

(c)

(d)

Monochromatic light is refracted from air into the glass of refractive index μ. The ratio of the wavelength of incident and refracted waves is

(a) 1 : μ

(b) 1 :

(c) μ : 1

(d) 1 : 1

In Young's double slit experiment, white light is used. The separation between the slits is b. The screen is at a distance d (d>> b) from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are

(a) λ =

(b) λ =

(c) λ =

(d) a, b

When a current is passed through water, acidified with a dilute sulphuric acid, the gases formed at the platinum electrodes are

(a) 1 vol. hydrogen (cathode) and 2 vol. oxygen (anode)

(b) 2 vol. hydrogen (cathode) and 1 vol. oxygen (anode)

(c) 1 vol. hydrogen (cathode) and 1 vol. oxygen (anode)

(d) 1 vol. oxygen (cathode) and 2 vol. hydrogen (anode)

For watt-less power in an AC circuit the phase angle between the current and voltage is.