Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

To produce an emission spectrum of hydrogen it needs to be ______.

What is the unit of mass when measured on the atomic scale?

The electric potential at a point on the equatorial line of an electric dipole is ______.

A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at a distance of 2 cm from the centre of the sphere is ______.

Whenever the magnetic flux linked with an electric circuit changes, an emf is induced in the circuit. This is called ______.

Which of the following I-V graph represents ohmic conductors?

Which of the following is correct for V-I graph of a good conductor?

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 ______.

Two inductors of inductance L each are connected in series with the opposite? magnetic fluxes. The resultant inductance is ______.

The magnetic flux linked with the coil (in Weber) is given by the equation- Փ = 5t² + 3t + 16. The induced EMF in the coil at time, t = 4 will be ______.

Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of j (current density) changes in an exact manner, while the current I remain unaffected. The agent that is essentially responsible for is ______.

A metal rod of length 10 cm and a rectangular cross-section of 1 cm × `1/2` cm is connected to a battery across opposite faces. The resistance will be ______.

Two cells of same emf E but internal resistance r₁ and r₂ are connected in series to an external resistor R (Figure). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.

Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1 mm. Conductor B is a hollow tube of outer diameter 2 mm and inner diameter 1 mm. Find the ratio of resistance R_A to R_B.

Suppose there is a circuit consisting of only resistances and batteries and we have to double (or increase it to n-times) all voltages and all resistances. Show that currents are unaltered. Do this for circuit of Example 3.7 in the NCERT Text Book for Class XII.

Consider the two idealized systems: (i) a parallel plate capacitor with large plates and small separation and (ii) a long solenoid of length L >> R, radius of cross-section. In (i) E is ideally treated as a constant between plates and zero outside. In (ii) magnetic field is constant inside the solenoid and zero outside. These idealised assumptions, however, contradict fundamental laws as below:

Verify the Gauss’s law for magnetic field of a point dipole of dipole moment m at the origin for the surface which is a sphere of radius R.

A square of side L meters lies in the x-y plane in a region, where the magnetic field is given by `B = Bo(2hati + 3hatj + 4hatk)`T, where B₀ is constant. The magnitude of flux passing through the square is ______.