The half-life of radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1:7 in a sample of a given rock. The age of the rock is estimated to be:

Home » The half-life of radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1:7 in a sample of a given rock. The age of the rock is estimated to be:

Physics | Physics

The half-life of radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1:7 in a sample of a given rock. The age of the rock is estimated to be:

Option A 100 years
Option B 40 years
Option C 60 years
Option D 80 years

Solution:

The correct option is Option C

i

More Material

The refractive index of glass is $1.5$ . What is the speed of light in glass? Speed of light in vacuum is $3.0 \times 10^{\mathrm{A}} \mathrm{ms}^{-1}$ .

Consider interference between two sources of intensities I and 4I. What will be the intensity at points where phase differences are:

Write two points of difference between interference and diffraction.

The frequency at which the impedance of the circuit boorens mavimum is
a $\frac{1}{2 \pi} \sqrt{\frac{1}{L C}+\frac{R^{2}}{L^{2}}}$
b $\frac{1}{2 \pi} \frac{1}{\sqrt{1 C}}$
c $\frac{1}{2 \mathrm{z}} \sqrt{\frac{1}{\mathrm{LC}}-\frac{\mathrm{R}^{2}}{\mathrm{~L}^{2}}}$
D $\frac{1}{2 \mathrm{e}} \frac{\mathrm{R}}{\mathrm{L}}$

State whether the following is true or false: The magnetic field inside a long circular coil carrying current will be parallel straight lines.

A galvanometer with resistance $100 \Omega$ gives full scale deflection with a current of $10 \mathrm{~mA}$ . The value of shunt, in order to convert it into an ammeter of 10 ampere range, will be
A $-10 \Omega$
B $1 \Omega$
C $0.1 \Omega$
D $0.01 \Omega$

Derive an expression for electric potential at a point due to an electric dipole. Discuss the special cases.

Derive an expression for the potential at a point due to a short dipole. Hence show what will be the potential at an axial and an equatorial point :

Find out the wavelength at which a black body at temperature $700 \mathrm{~K}$ emits maximum energy

Name the type of lens which is used to correct? i) Myopia ii) Hypermetropia.

How does concave lens correct myopia?
A Increases the curvature of the eye lens
B Forms the image of the object at the retina
C Decreases the elongation of the eyeball
D All of the above Correct option is (B) Forms the image of the object at the retina

Explain end-on position and broad side-on position of a bar magnet.

← Previous Next →

More Material

The refractive index of glass is $1.5$ . What is the speed of light in glass? Speed of light in vacuum is $3.0 \times 10^{\mathrm{A}} \mathrm{ms}^{-1}$ .

Consider interference between two sources of intensities I and 4I. What will be the intensity at points where phase differences are:

Write two points of difference between interference and diffraction.

State whether the following is true or false: The magnetic field inside a long circular coil carrying current will be parallel straight lines.

A galvanometer with resistance $100 \Omega$ gives full scale deflection with a current of $10 \mathrm{~mA}$ . The value of shunt, in order to convert it into an ammeter of 10 ampere range, will be
A $-10 \Omega$
B $1 \Omega$
C $0.1 \Omega$
D $0.01 \Omega$

Derive an expression for electric potential at a point due to an electric dipole. Discuss the special cases.

Derive an expression for the potential at a point due to a short dipole. Hence show what will be the potential at an axial and an equatorial point :

Find out the wavelength at which a black body at temperature $700 \mathrm{~K}$ emits maximum energy

Name the type of lens which is used to correct? i) Myopia ii) Hypermetropia.

How does concave lens correct myopia?
A Increases the curvature of the eye lens
B Forms the image of the object at the retina
C Decreases the elongation of the eyeball
D All of the above Correct option is (B) Forms the image of the object at the retina

Explain end-on position and broad side-on position of a bar magnet.

Sign up now and study all subjects for free

Class

Syllabus

Question Papers

Social Media

Apps