1
JEE Advanced 2016 Paper 2 Offline
+3
-1
An accident in a nuclear laboratory resulted in deposition of a certain amount of radioactive material of half-life 18 days inside the laboratory. Tests revealed that the radiation was 64 times more than the permissible level required for safe operation of the laboratory. What is the minimum number of days after which the laboratory can be considered safe for use?
A
64
B
90
C
108
D
120
2
JEE Advanced 2016 Paper 2 Offline
+3
-1
The electrostatic energy of Z protons uniformly distributed throughout a spherical nucleus of radius R is given by $$E = {3 \over 5}{{Z(Z - 1){e^2}} \over {4\pi {\varepsilon _0}R}}$$

The measured masses of the neutron, $$_1^1H$$, $$_7^{15}N$$ and $$_8^{15}O$$ are 1.008665u, 1.007825u, 15.000109u and 15.003065u, respectively. Given that the radii of both the $$_7^{15}N$$ and $$_8^{15}O$$ nuclei are same, 1 u = 931.5 MeV/c2 (c is the speed of light) and e2/(4$$\pi$$$${{\varepsilon _0}}$$) = 1.44 MeV fm. Assuming that the difference between the binding energies of $$_7^{15}N$$ and $$_8^{15}O$$ is purely due to the electrostatic energy, the radius of either of the nuclei is (1 fm = 10$$-$$15 m)
A
2.85 fm
B
3.03 fm
C
3.42 fm
D
3.80 fm
3
JEE Advanced 2015 Paper 1 Offline
+8
-4

Match the nuclear processes given in Column I with the appropriate option(s) in Column II:

A
(A)→(R) or (RT), (T); (B)→(P), (S); (C)→(Q), (T); (D)→(R)
B
(A)→(R), (T); (B)→(Q), (S); (C)→(Q), (T); (D)→(R)
C
(A)→(R) or (RT), (T); (B)→(P), (S); (C)→(S), (T); (D)→(R)
D
(A)→(P), (T); (B)→(P), (S); (C)→(Q), (T); (D)→(R)
4
JEE Advanced 2014 Paper 2 Offline
+3
-1

If $$\lambda$$Cu is the wavelength of K$$\alpha$$ X-ray line of copper (atomic number 29) and $$\lambda$$Mo is the wavelength of the K$$\alpha$$ X-ray line of molybdenum (atomic number 42), then the ratio $$\lambda$$Cu/$$\lambda$$Mo is close to

A
1.99
B
2.14
C
0.50
D
0.48
EXAM MAP
Medical
NEET