Alternating Current — Physics STD 12 Science — Question

A slit of size 0.15 cm is placed at 2.1 m from a screen. On illuminated it by a light of wavelength 5 × 10^–5 cm. The width of central maxima will be

(a) 70 mm

(b) 0.14 mm

(c) 1.4 mm

(d) 0.14 cm

In Fig., assuming the diodes to be ideal:

Consider a capacitor-charging circuit. Let Q₁ be the charge given to the capacitor in a time interval of 10ms and Q₂ be the charge given in the next time interval of 10ms. Let 10mC charge be deposited in time interval t₁ and another 10mC charge be deposited in the next time interval t₂.

Two resistances are joined in parallel whose resultant is  ohm. One of the resistance wire is broken and the effective resistance becomes 2Ω. Then the resistance in ohm of the wire that got broken was

(a) 3/5

(b) 2

(c) 6/5

(d) 3

One proton beam enters a magnetic field of  T normally, Specific charge = . velocity = . What is the radius of the circle described by it

(a) 0.1 m

(b) 1 m

(c) 10 m

(d) None of these

A magnet of magnetic moment M is suspended in a uniform magnetic field B. The maximum value of torque acting on the magnet is

The minimum distance between an object and its real image formed by a convex lens of focal length f is:

Young’s double slit experiment is performed with light of wavelength 550 nm. The separation between the slits is 1.10 mm and screen is placed at distance of 1 m. What is the distance between the consecutive bright or dark fringes

(a) 1.5 mm

(b) 1.0 mm

(c) 0.5 mm

(d) None of these

Waves in decreasing order of their wavelength are:

The phase difference between current and voltage in an A.C. circuit containing capacitance only is :