Nuclei — Physics STD 12 Science — Question

The radius of the shortest orbit in a one-electron system is 18 pm. It may be

In the Young’s double slit experiment with sodium light. The slits are 0.589 m a part. The angular separation of the third maximum from  the central maximum will be (given 𝜆 = 589 mm)

(a)

(b)

(c)

(d)

Which of the following describe that two lighter atoms combine to form one heavier atom?

If flux of the electric field through a closed surface is zero:

1. The electric field must be zero everywhere on the surface.
2. The electric field may be zero everywhere in the surface.
3. The charge inside the surface must be zero.
4. The charge in the vicinity of the surface must be zero.

Assertion  :   Faraday’s laws are consequences of conservation of energy.

Reason      : In a purely resistive ac circuit, the current lags behind the e.m.f. in phase.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then the ratio of the wavelengths is nearest to?

Consider a magnetic dipole kept in the north to south direction. Let P₁, P₂, Q₁, Q₂ be four points at the same distance from the dipole towards north, south, east and west of the dipole respectively. The directions of the magnetic field due to the dipole are the same at:

1. P₁ and P₂
2. Q₁ and Q₂
3. P₁ and Q₁
4. P₂ and Q₂

A point object O is placed in front of a glass rod having spherical end of radius of curvature 30 cm.  The image would be formed at

(a) 30 cm left

(b) Infinity

(c) 1 cm to the right

(d) 18 cm to the left

The plate resistance of a triode is 2.5 × 10⁴ W and mutual conductance is 2 × 10^–3 mho. What will be the value of amplification factor

(a) 50

(b) 1.25 × 107

(c) 75

(d) 2.25 × 107

Photoelectric effect proves that light wave :