1
JEE Main 2022 (Online) 29th June Evening Shift
Numerical
+4
-1

The half life of a radioactive substance is 5 years. After x years a given sample of the radioactive substance gets reduced to 6.25% of its initial value. The value of x is ____________.

2
JEE Main 2022 (Online) 29th June Morning Shift
Numerical
+4
-1

$$\sqrt {{d_1}}$$ and $$\sqrt {{d_2}}$$ are the impact parameters corresponding to scattering angles 60$$^\circ$$ and 90$$^\circ$$ respectively, when an $$\alpha$$ particle is approaching a gold nucleus. For d1 = x d2, the value of x will be ____________.

3
JEE Main 2022 (Online) 27th June Morning Shift
Numerical
+4
-1

A beam of monochromatic light is used to excite the electron in Li+ + from the first orbit to the third orbit. The wavelength of monochromatic light is found to be x $$\times$$ 10$$-$$10 m. The value of x is ___________.

[Given hc = 1242 eV nm]

4
JEE Main 2022 (Online) 24th June Evening Shift
Numerical
+4
-1

A sample contains 10$$-$$2 kg each of two substances A and B with half lives 4 s and 8 s respectively. The ratio of their atomic weights is 1 : 2. The ratio of the amounts of A and B after 16 s is $${x \over {100}}$$. The value of x is ___________.

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