A rocket is launched normal to the surface of earth, away from the Sun, along the line joining the Sun and the Earth. The Sun is 3 *10^5 times heavier than the Earth and is at a distance 2.5 *10^4 times larger than the radius of the Earth. The escape velocity from Earth’s gravitational field is ve = 11.2 km /s The minimum initial (vs) required for the rocket to be able to leave the Sun-earth system is closest to(Ignore the rotation and revolution of the Earth and the presence of any other planet).

Rahul Kumar Physics 30 Jul, 2017 1 Answer 331 views

An electron in a hydrogen atom undergoes a transition from an orbit with quantum numebr ni to another with quantum number nf. Vi and Vf are respectively the initial and final potential energies of the electon. If vi/ vf =6.25, Then what is smallest possible nf is

Preeti Rai Chemistry 29 Jul, 2017 1 Answer 454 views



A crystalline solid of a pure substance has a face-centred cubic structure with a cell edge of 400 pm. If the density of the substance in the crystal is 8 g cm-3, then the number of atoms present in 256 g of the crystal is N × 1024. The value of N?

Rahul Kumar Chemistry 28 Jul, 2017 1 Answer 1185 views







Two balls are dropped to the ground from different heights. One ball is dropped 2s after the other but they both strike the ground at the same time. If the first ball takes 5s to reach the ground, then the difference in initial heights is (g = 10 ms–2) 40

Preeti Rai Physics 23 Jul, 2017 1 Answer 4568 views
















Mr. Sharma and Mr. Arora are family friends and they decided to go for a trip with family . For the trio they reserved their rail tickets . Mr. Arora has not taken a half ticket for his child who is 6 years old where as Mr, Sharma has taken half tickets for his two children who are 6 year and 8.5 year.A railway half ticket costs half of the full fare but the reservation charges are the same as on a FULL TICKET. MR AND MRS ARORA PAID 1700,WHILE MR AND MRS SHARMA PAID 2700. Find the full share of one ticket and reservation charges per ticket.

Ashish Maurya Maths 07 Jul, 2017 1 Answer 1990 views