When monochromatic light is incident on a metal surface, doubling the intensity of the incident light while keeping the wavelength the same will cause the kinetic energy of emitted electrons to remain the same.
Increasing the wavelength of incident radiation in photoemission results in a decrease in the average kinetic energy of photoelectrons.
Reflection of a photon from a mirror causes a change in momentum that is twice the original momentum of the photon.
When n photons strike a metal surface, the total momentum exerted is equal to the total momentum of n photons, which is denoted by ‘p’.
A photon with a wavelength of 900nm behaves as if it has a mass of 2.46 x 10^-36kg.
A particle with de Broglie wavelength λ and mass m has a velocity of v = 2 × 10^6 m/s.
The diffracted proton from a crystal in the Davisson-Germer experiment exhibits wave-like properties.
Placing a diffraction grating in the path of a light beam reveals its wave property.
Energetic particles are used in electron microscopes because of the very short wavelength associated with their high kinetic energy.
Electric and magnetic fields are used to create a converging source of electrons in an electron microscope.
A three-dimensional image is obtained using a scanning electron microscope.
The uncertainty in momentum and position of particles is due to their property of matter and radiation.
To confine an electron in a box of radius 10^-14m, its speed should be greater than the speed of light.
The energy radiated is directly proportional to the fourth power of the Kelvin’s temperature, according to Stephen’s law.
The Compton effect proves the photon theory of light.
Electrons in an atom move in orbits as standing wave motions.
A converging lens is one that converges a beam of parallel rays to a point.
The principal axis of a lens is the line passing through the center of the lens perpendicular to its surface.
The unit of lens power is the diopter.
A concave lens has a negative power.
If an object is placed beyond 2f of a converging lens, the image formed will be real and inverted.
The magnifying power of a simple microscope increases as the focal length decreases.
The least distance of distinct vision for a normal eye is 25 cm.
A lens that fails to converge light rays to a single point due to its large aperture suffers from spherical aberration.
The focal length of a combination of a convex lens of focal length f1 and a concave lens of focal length f2 in contact is f1f2 / (f1 – f2).
The refractive index of the core of a multimode step-index fiber is higher than that of the cladding.
The final image produced by a compound microscope is virtual and inverted.
For normal adjustment, the length of an astronomical telescope is fo + fe.
The resultant focal length of two convex lenses with equal focal length f is f / 2.
The least distance of distinct vision increases with age.
The magnification produced by a lens when the image of a 5 mm high object is 1 cm high is 2.
A convex lens gives a virtual image only when the object is placed between the principal focus and the optical center.
The minimum distance between an object and its real image in a convex lens is 4f.
The diopter power of a concave lens with a focal length of 10 cm is 10 diopters.
The focus of an optical system is the point where incident parallel rays of light converge or appear to diverge.
The critical angle for glass is 42°.
In an optical fiber transmission system, repeaters are used to regenerate the dim light signal.
The magnifying power of a simple microscope increases with a decrease in focal length.
The errors in the transmission of power through an optical fiber can be minimized by using a graded index fiber.
A collimator in a spectrometer is used to produce parallel beams of light.
The repeaters in an optical fiber transmission system are separated through a distance of 100 km in newer systems.
The formula C = 16fd was devised by Michelson to calculate the speed of light.
A convex lens acts as a diverging lens if the object is placed beyond the center of curvature or within the focal length.
The equation θ = 1.22λ/D was devised by Raleigh to describe the angular resolution of optical instruments.
Michelson calculated the speed of light using a spectrometer.
Electrons cannot exist in the nucleus; their size compared to protons and neutrons is very small.
The characteristic X-ray spectrum is due to the bombardment of the target by electrons.
Excited atoms return to their ground state in approximately 10^-8 seconds.
Hydrogen atoms have discrete line spectra.
The energy levels in an atom are not equally spaced.
The wavelength of the X-ray emitted with the greatest energy is 1.54 Å.
The electronic configuration of an atom with 15 electrons is 1s²2s²2p⁶3s²3p³.
The element with atomic number 6 is found in Group 16 and Period 2.
A half-life period is independent of temperature, pressure, and other environmental factors.
Carbon-14 dating can be used to determine the age of ancient wooden artifacts.
The half-life of uranium-238 is approximately 4.5 billion years.
The most penetrating and dangerous form of nuclear radiation is gamma rays.
Elements with atomic numbers greater than 92 are all synthetic and radioactive.
The energy released in nuclear reactions is obtained from the conversion of mass into energy.
The sum of the number of protons and neutrons in an atom’s nucleus is called the mass number.
The fundamental force that holds the nucleus of an atom together is the strong nuclear force.
Neutrons are electrically neutral particles found in the nucleus of an atom.
The process of nuclear fission involves the splitting of a heavy nucleus into two lighter nuclei along with the release of a large amount of energy.
The process of nuclear fusion involves the combining of two light nuclei to form a heavier nucleus, releasing a tremendous amount of energy.
A Geiger-Muller counter is used to detect and measure radioactivity.
The decay constant of a radioactive substance is a measure of the probability of its decay per unit time.
The atomic number of an element determines its chemical properties and is equal to the number of protons in its nucleus.
Isotopes of an element have the same number of protons but a different number of neutrons in their nuclei.
The process of radioactive decay is a random process that cannot be influenced by external factors.
The primary source of energy in the sun and other stars is nuclear fusion.
The mass defect in a nuclear reaction is converted into energy according to Einstein’s equation E=mc².
The main difference between nuclear reactions and chemical reactions is the involvement of the nucleus in nuclear reactions.
A positron is a positively charged electron and is emitted in certain types of radioactive decay.
The binding energy per nucleon is highest in iron, making it the most stable nucleus.
The half-life of a radioactive substance is the time it takes for half of the initial quantity of the substance to decay.
The nucleus of an atom is much smaller and denser than the surrounding electron cloud.
The process of beta decay involves the conversion of a neutron into a proton and the emission of a beta particle (electron) and an antineutrino.
The process of alpha decay involves the emission of an alpha particle, which consists of two protons and two neutrons.
The neutron-to-proton ratio in a stable nucleus generally increases with increasing atomic number.
The concept of the neutrino was introduced by Wolfgang Pauli to explain the continuous spectrum observed in beta decay.
Neutrinos are electrically neutral and interact very weakly with matter, making them difficult to detect.
The half-life of a radioactive substance determines the rate of its decay and is a characteristic property of the substance.
The nucleus of a radioactive atom undergoes decay to achieve a more stable configuration.
The process of gamma decay involves the emission of a gamma photon, which is a high-energy photon, to release excess energy from an excited nucleus.
The decay of a radioactive substance follows first-order kinetics, which means that the rate of decay is proportional to the amount of the substance present.
The decay series of uranium-238 eventually leads to the stable nucleus of lead-206.
Carbon-14 is produced in the upper atmosphere through the interaction of cosmic rays with nitrogen-14.
The age of a sample can be determined using carbon-14 dating based on the ratio of carbon-14 to carbon-12 isotopes present in the sample.
The process of artificial transmutation involves bombarding a nucleus with particles to induce a nuclear reaction and create new elements.
The nucleus of an atom contains nearly all of its mass in a very small volume, while the electrons occupy a much larger volume.
The process of nuclear fusion releases a significant amount of energy and is the process that powers hydrogen bombs.
The binding energy of a nucleus is the energy required to completely disassemble it into its individual protons and neutrons.
The decay of a radioactive substance is a random process, and the exact time of decay for a single nucleus cannot be predicted.
A beta particle emitted in beta decay is an electron if it’s a negatively charged beta particle (β-), and it’s a positron if it’s a positively charged beta particle (β+).
The energy released in nuclear reactions is much greater than that released in chemical reactions due to the conversion of mass into energy according to Einstein’s equation.
The rate of decay of a radioactive substance is usually measured by its half-life, which is the time it takes for the activity of the substance to decrease by half.
The process of nuclear fission can release an enormous amount of energy and is the principle behind nuclear power reactors and atomic bombs.
The process of alpha decay reduces the mass number of the parent nucleus by four units and the atomic number by two units.
The emission of a beta particle in beta decay occurs when a neutron in the nucleus transforms into a proton, accompanied by the release of an electron and an antineutrino.
The concept of the neutrino was proposed by Wolfgang Pauli in 1930 to account for the apparent violation of conservation of energy and angular momentum in beta decay.
