Work Energy and Power Class 9 One-Shot Full Lecture + Quiz | 2021 Exam Preparation | Triumph Series

in an experimental set up to study the photoelectric effect a point soure fo light of power 3.2xx10^(-3) W was taken. The source can emit monoenergetic photons of energy 5eV and is located at a distance of 0.8 m from the centre of a stationary metallic sphere of work-function 3.0 eV. The radius of the sphere is r = 8..10^(-3) m. The efficiency of photoelectric emission is one for every 10^6 incident photons. Based on the information given above answer the questions given below. (Assume that the sphere is isolated and photoelectrons are instantly swepts away after the emission). de-Broglie wavelength of the fastest moving photoelectron is

in an experimental set up to study the photoelectric effect a point soure fo light of power 3.2xx10^(-3) W was taken. The source can emit monoenergetic photons of energy 5eV and is located at a distance of 0.8 m from the centre of a stationary metallic sphere of work-function 3.0 eV. The radius of the sphere is r = 8..10^(-3) m. The efficiency of photoelectric emission is one for every 10^6 incident photons. Based on the information given above answer the questions given below. (Assume that the sphere is isolated and photoelectrons are instantly swepts away after the emission). Time after which photoelectric emission stops is

(a) What is the difference between gravitational potential energy and elastic potential energy ? Give one example of a body having gravitational potential energy and another having elastic potential energy. (b) If 784 J of work was done in lifting a 20 kg mass, calculate the height through which it was lifted. ( g = 9.8 m//s^(2) )

Find the work and power required to move the conductor of length l shown in the fig. one full turn in the anticlockwise direction at a rotational frequency of n revolutions per second if the magnetic field is of magnitude B_(0) everywhere and points radially outwards from Z-axis. The figure shows that surface traced by the wire AB.

Gas authority of India Ltd . (GAIL) is carrying on various projects of energy and power . Majority of its shares are held by government of India . It is registered under Companies Act , 1956 and enjoy all the characteristics of a company . The board of directors are appointed by the government . The Board and shareholders are responsible for the efficient working of the company . The company prepares its annual report and submit to appropriate authorities. (a) Name the type of public sector enterprise referred in above para. (b) Government dusy shares in whose name ? (c ) Where does goverment companies submit their reports?

In a photoelectric effect set up, a point source of light of power 3.2 xx10^(-3) W emits monoenergetic photons of energy 5eV .The source is located at a distance of a stationary metallic sphere of work function 3eV and radius 8xx10^(-3)m .The efficiency of photoelectron emission is one for every 10^(6) incident photons.Assume that the sphere is isolated and initially neutral and the photoelectrons are initially swept away after emission. Find the maximum kinetic energy of photoelectrons: