A radiactive substance emits 100 beta particles in the first 2s and 50 beta
A radiactive substance emits 100 beta particles in the first 2s and 50 beta particles in the next 2s. The mean life of the sample is
Options
(a) 4 s (b) 2 s […]
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A nucleus ᴢXᴬ emits an α- particle with velocity v. The recoil speed of the daughter
A nucleus ᴢXᴬ emits an α- particle with velocity v. The recoil speed of the daughter nucleus is
Options
(a) A-4/4v (b) 4v/A-4 (c) v (d) v/4
Correct Answer:
4v/A-4
Explanation:
According to the […]
Pick out the correct statements from the following
Pick out the correct statements from the following I. Electron emission during β-decay is always accompanied by neutrons II. Nuclear force is charge independent III. Fusion is the chief source of stellar energy
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λ₁ and λ₂ are used to illuminate the slits. β₁ and β₂ are the corresponding fringe
λ₁ and λ₂ are used to illuminate the slits. β₁ and β₂ are the corresponding fringe widths. The wavelength λ₁ can produce photoelectric effect when incident on a metal. But the wavelength λ₂ cannot produce […]
The concentric spheres of radii R and r have positive charges q₁ and q₂ with equal
The concentric spheres of radii R and r have positive charges q₁ and q₂ with equal surface charge densities. What is the electric potential at their common centre?
Options
(a) σ/ε₀(R+r) (b) σ/ε₀(R-r) […]
Two metal spheres of radii 0.01m and 0.02m are given a charge of 15mC and 45mC
Two metal spheres of radii 0.01m and 0.02m are given a charge of 15mC and 45mC, respectively. They are then connected by a wire. The final charge on the first sphere is……x10⁻³C.
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A small oil drop of mass 10⁻⁶kg is hanging in at rest between two plates seperated
A small oil drop of mass 10⁻⁶kg is hanging in at rest between two plates seperated by 1mm having a potential difference of 500 V. The charge on the drop is (g=10ms⁻²)
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Two identical circular coils A and B are kept on a horizontal tube
Two identical circular coils A and B are kept on a horizontal tube side by side without touching each other. If the current in the coil A increases with time, in response, the coil B […]
Masses of three wires of copper are in the ratio of 1:3:5 and their lengths
Masses of three wires of copper are in the ratio of 1:3:5 and their lengths are in the ratio of 5:3:1. The ratio of their electrical resistances is
Options
(a) (1:3:5) (b) (5:3:1) […]
The ionisation energy of an electron in the ground state of helium atom is 24.6 eV.
The ionisation energy of an electron in the ground state of helium atom is 24.6 eV. The energy required to remove both the electron is
Options
(a) 51.8 eV (b) 79 eV (c) […]