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Determine the distance of the closest approach when an alpha particle of kinetic energy 4.5 MeV strikes a nucleus of Z = 80, stops and reverses its direction.
Concept: Radioactivity >> Alpha Decay
The figure shows the plot of binding energy (BE) per nucleon as a function of mass number A. The letters A, B, C, D, and E represent the positions of typical nuclei on the curve. Point out, giving reasons, the two processes (in terms of A, B, C, D, and E ), one of which can occur due to nuclear fission and the other due to nuclear fusion.
Concept: Mass-energy and Nuclear Binding Energy >> Nuclear Binding Energy
Identify the nature of the radioactive radiations emitted in each step of the decay process given below.
`""_Z^A X -> _Z^A _-1^-4 Y ->_Z^A _-1^-4 W`
Concept: Law of Radioactive Decay
A radioactive substance disintegrates into two types of daughter nuclei, one type with disintegration constant λ1 and the other type with disintegration constant λ2 . Determine the half-life of the radioactive substance.
Concept: Law of Radioactive Decay
Answer the following question.
Draw the curve showing the variation of binding energy per nucleon with the mass number of nuclei. Using it explains the fusion of nuclei lying on the ascending part and fission of nuclei lying on the descending part of this curve.
Concept: Mass-energy and Nuclear Binding Energy >> Nuclear Binding Energy
James Chadwick, in 1932 studied the emission of neutral radiations when Beryllium nuclei were bombarded with alpha particles. He concluded that emitted radiations were neutrons and not photons. Explain.
Concept: Atomic Masses and Composition of Nucleus
Two nuclei may have the same radius, even though they contain different numbers of protons and neutrons. Explain.
Concept: Atomic Masses and Composition of Nucleus
The radius of \[\ce{^27_13X}\] nucleus is R. The radius of \[\ce{^125_53Y}\] nucleus will be ______.
Concept: Size of the Nucleus
Calculate the binding energy of an alpha particle in MeV. Given
mass of a proton = 1.007825 u
mass of a neutron = 1.008665 u
mass of He nucleus = 4.002800 u
1u = 931 MeV/c2
Concept: Mass-energy and Nuclear Binding Energy >> Nuclear Binding Energy
Distinguish between a conductor and a semi conductor on the basis of energy band diagram
Concept: Energy Bands in Conductors, Semiconductors and Insulators
The following figure shows the input waveforms (A, B) and the output waveform (Y) of a gate. Identify the gate, write its truth table and draw its logic symbol.
Concept: Digital Electronics and Logic Gates
Briefly explain how the output voltage/current is unidirectional.
Concept: Application of Junction Diode as a Rectifier
What happens when a forward bias is applied to a p-n junction?
Concept: Semiconductor Diode
When is a transistor said to be in active state?
Concept: Junction Transistor >> Transistor: Structure and Action
Draw a circuit diagram of a p-n-p transistor and explain how it works as a transistor amplifier
Concept: Junction Transistor >> Transistor as an Amplifier (Ce-configuration)
Write clearly, why in the case of a transistor (i) the base is thin and lightly doped
Concept: Transistor and Characteristics of a Transistor
Write clearly, why in the case of a transistor (ii) the emitter is heavily doped.
Concept: Transistor and Characteristics of a Transistor
What causes the setting up of high electric field even for small reverse bias voltage across the diode?
Concept: Semiconductor Diode
If a small voltage is applied to a p-n junction diode, how will the barrier potential be affected when it is (i) forward biased
Concept: Special Purpose P-n Junction Diodes
If a small voltage is applied to a p-n junction diode, how will the barrier potential be affected when it is(ii) reveres biased?
Concept: Special Purpose P-n Junction Diodes
