In Rutherford's alpha scattering experiment using gold foil, the kinetic energy of the alpha particle was 1.2 x 10^-12J. For a head on collision, using the formula K.E. = $\frac{1}{4{\mathrm{\pi \epsilon }}_0}$x 2Ze²/r₀ , what may be the magnitude of r₀ [ The nuclear radius of gold, Z=79; $\frac{1}{4{\mathrm{\pi \epsilon }}_0}$= 9 x 10⁹ new-ton/meter² coulomb^-2, e= 1.6x10^-19 coulomb]

1. 3 x 10^-14m

2. 1.3 x 10^-14m

3. 2.1 x 10^-14m

4. 4.3 x 10^-14m

If frequency of the X-rays produced using an element as anti-cathode is found to be 2500 sec^-1, the atomic number of used element is (a, b= 1)

1. 51

2. 49

3. 56

4. 72

When the atoms of gold sheet are bombarded with a beam of $\alpha$ -particles, only a few a-particles get deflected where as most of them go straight undeflected. This is because:

An element with atomic mass Z consists of two isotopes of mass number Z-1 and Z + 2. The percentage abundance of the heavier isotope is -

1. 0.25

2. 33.3

3. 66.6

4. 75

Two isotopes of Boron are found in the nature with atomic weights 10.01(I) and 11.01(II). The atomic weight of natural Boron is 10.81. The percentage of (I) and (II) isotopes in it are respectively-

1. 20 and 80

2. 10 and 90

3. 15 and 75

4. 30 and 70

Rutherford's scattering experiment is related to the size of the-

1. Nucleus

2. Atom

3. Electron

4. Neutron

Arrange the following particles in increasing order of values of e/m ratio: Electron (e), proton (p), neutron (n) and α-particle (α)

1. n, p, e, α

2. n, α, p, e

3. n, p, α, e

4. e, p, n, α

Mass of neutron is ........................times the mass of an electron-

1. 1840

2. 1480

3. 2000

4. None of the above

Isodiaphers among the following options is :

1.  ${}_6{}^{14}C$ and ${}_{11}{}^{23}N$ 

2.  ${}_{12}{}^{24}Mg$  and ${}_{11}{}^{23}C$ 

3.  ${}_2{}^{4}He$  and ${}_8{}^{16}O$ 

4.  ${}_6{}^{12}C$  and ${}_7{}^{15}N$  

The incorrect statement regarding the characteristics of X-rays is :

1. The radiation can ionize the gas

2. It causes a fluorescence effect on ZnS

3. It is deflected by electric and magnetic fields

4. Have a shorter wavelength than ultraviolet rays