JEE Main Test 9...

In an experiment to determine the focal length (f ) of a concave mirror by the u-v method, a student places the object pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted image from a distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin.Then,

Three numbers are chosen at random from 1 to 20. The probability that they are consecutive, is

The probability of simultaneous occurrence of atleast one of two events A and B is p. If the probability that exactly one of A , B occurs is q, then P (A' )+ P (B') is equal to

A photodetector used to detect the wavelength of 1700 nm, has energy gap of about

₉₂U²³⁵ undergoes successive disintegrations with the end product of ₈₂Pb²⁰³. The number α and β-particles emitted are

The energy released in the explosion of an atom bomb is mainly due to

When electric current is passed through acidified water for 1930 s, 1120 mL, of H₂ gas is collected (at STP) at the cathode. What is the current passed in amperes?