STANDARD Physics Class 12 Questions

Which one of the following is not correct about Lorentz Force?

The current in a wire varies with time according to the equation I = 4 + 2t, where I is in ampere and t is in second. The quantity of charge which has to be passed through a cross-section of the wire during the time t = 2 s to t = 6 s is

Displacement current goes through the gap between the plates of a capacitor when the charge on the capacitor

The number of images formed by the lens, if an object is placed on the axis of the lens is:

In a Geiger-Marsden experiment. Find the distance of closest approach to the nucleus of a 7.7 MeV α-particle before it comes momentarily to rest and reverses its direction. (Z for gold nucleus = 79)

Wavefront is the locus of all points, where the particles of the medium vibrate with the same

Which of the following options is true?

Which of the following is correct about magnetic monopole?

A cup contains 250 g of water. Find the total positive charge present in the cup of water.

This question contains Statement-1 and Statement-2 of the four choices given after the statements, choose the one that best describes the two statements. Statement-1: For a charged particle moving from point P to point Q, the net work done by an electrostatic field on the particle is independent of the path connecting point P to point Q. Statement-2: The net work done by a conservative force on an object moving along a closed loop is zero.

Alternating current cannot be measured by DC ammeter because

Nucleons are

The set which represents the isotope, isobar and isotone respectively is

A circular loop of radius R carrying a current I is placed in a uniform magnetic field B perpendicular to the loop. The force on the loop is

The charge on a parallel plate capacitor varies as q = q₀ cos 2πνt. The plates are very large and close together (area = A, separation = d). The displacement current through the capacitor is

Which of the following is not correct about the magnetic field lines?

A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply. The rms value of current in the circuit is

The phenomena which is not explained by Huygen's construction of wavefront

The number of electrons that must be removed from an electrically neutral silver dollar to give it a charge of +2.4 C is

In the Geiger-Marsden scattering experiment the number of scattered particles detected are maximum and minimum at the scattering angles respectively at

In an atom electrons revolves around the nucleus along a path of radius 0.72 Å making 9.4 × 10¹⁸ revolution per second. The equivalent current is (e = 1.6 × 10⁻¹⁹)

The magnetic flux linked with a coil of N turns of area of cross section A held with its plane parallel to the field B is

Which is the correct form of the graph of angle of incidence vs angle of deviation for a triangular prism during the parallax method?

A circular disc of radius 0.2 m is placed in a uniform magnetic field of induction \( \frac{1}{\pi} \) Wb m⁻² in such a way that its axis makes an angle of 60° with B. The magnetic flux linked with the disc is

In the case of light waves from two coherent sources S₁ and S₂, there will be constructive interference at an arbitrary point P, if the path difference S₁P-S₂P is

The relation between an ac voltage source and time in SI units is V = 120 sin(100 πt) cos(100 πt) V. The value of peak voltage and frequency will be respectively

The voltage V and current I graphs for a conductor at two different temperatures T₁ and T₂ are shown in the figure. The relation between T₁ and T₂ is

The conduction current is same as displacement current when source is

Match the corresponding entries of column 1 with column 2 where m is the magnification produced by the mirror.

The refractive index of the material of a prism is √2 and the angle of the prism is 30°. One of the two refracting surface of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is?

An ac source is of 200/√2 V, 50 Hz. The value of voltage after 1/600 s from the start is

For the case given in previous question, which of the following is the path difference for destructive interference?

A coil of area 0.4 m² has 100 turns. A magnetic field of 0.04 Wb m⁻² is acting normal to the coil surface. If this magnetic field is reduced to zero in 0.01 s, then the induced emf in the coil is

A wire with 15 Ω resistance is stretched by one tenth of its original length and volume of wire is kept constant. Then its resistance will be

For which of the following dependences of drift velocity vₐ on electric field E, is Ohm's law obeyed?

An equiconvex lens is cut into two halves a long (i) XOX and (ii) YOY as shown in the figure let f, f', f'' be the focal lengths of the complete lens of each half in case (i) and of each half in case (ii) respectively. Choose the correct statement from the following:

Two light waves superimposing at the mid-point of the screen are coming from coherent sources of light with phase difference 3π rad. Their amplitudes are 1 cm each. The resultant amplitude at the given point will be

If V = 100 sin(100t) V and I = 100 sin(100t + π/3) mA are the instantaneous values of voltage and current, then the rms values of voltage and current are respectively

A square of side x m lies in the x-y plane in a region, where the magnetic field is given by B = B₀(3i + 4j + 5k)T, taking B₀ as constant. The magnitude of flux passing through the square is

A charged particle having drift velocity of 7.5 × 10⁻⁴ m s⁻¹ in electric field of 3 × 10⁻¹⁰ V m⁻¹, mobility is

Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is π/2 at point A and π at point B. Then the difference between the resultant intensities at A and B is

In an ac circuit, V and I are given by V = 150sin(150t)V and I = 150sin(150t + π/3) A. The power dissipated in the circuit is

The magnetic flux through a coil perpendicular to its plane and directed into paper is varying according to the relation ϕ = (2t² + 4t + 6) mWb. The emf induced in the loop at t = 4 s is

Which one among the following does not represent Maxwell's equation?

The energies E₁ and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e., λ₁ and λ₂ will be

The phase relationship between current and voltage in a pure resistive circuit is best represented by

A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1 mm s⁻¹. The induced emf when the radius is 2 cm, is

An electromagnetic wave can be produced, when charge is

The refracting angle of a prism is A, and refractive index of the material of the prism is cot(A/2). The angle of minimum deviation is:

Light from two coherent sources of the same amplitude A and wavelength λ, illuminates the screen. The intensity of the central maximum is I₀. If the sources were incoherent, the intensity at the same point will be