# Physics 2nd Paper CQ-Rajshahi Board-2023

প্রশ্ন ·সময় ২ ঘণ্টা ৩৫ মিনিট

1. Mass of a piece of Radium is $5 \mathrm{~g}$. No of disintegrated atoms are almost $3.7 \times 10^{10}$ from $\lg$ of Radium $\left({ }^{266} _{88} \mathrm{Ra}\right)$ per second. By observing the data a student told after 600 years $2 \mathrm{~g}$ of radium will be remain there.

Rajshahi Board-2023
ব্যাখ্যা আনলক করতে চর্চা প্রিমিয়াম এ আপগ্রেড করো

2. In Young's double slit experiment wavelength of the 4 $5896 \AA$ and distance between two slits is $2 \mathrm{~mm}$ and distance between slits and the screen is $\mathrm{Im}$. After that distance between the slits is changed as it becomes half of the previous distance and also the distance between slits and screen is changed and it becomes twice of the initial distance.

Rajshahi Board-2023
ব্যাখ্যা আনলক করতে চর্চা প্রিমিয়াম এ আপগ্রেড করো

3. An astronaut starts his journey from earth's surface towards Mars along $Y$-axis (in the figure) with a velocity of $0.1 \mathrm{C}$ with a spaceship. In the figure a piece of paper of rectangular shape is shown in the spaceship.

Rajshahi Board-2023
ব্যাখ্যা আনলক করতে চর্চা প্রিমিয়াম এ আপগ্রেড করো

4. In photoelectric effect a sodium plate is illuminated with rays of light of frequency $0.714 \times 10^{15} \mathrm{~Hz}$ and for that stopping potential is $0.65 \mathrm{~V}$. If the wavelength is $3.1 \times 10^{2} \mathrm{~nm}$ stopping potential becomes $1.69 \mathrm{~V}$.

Rajshahi Board-2023
ব্যাখ্যা আনলক করতে চর্চা প্রিমিয়াম এ আপগ্রেড করো

5. In a thermodynamic system $14 \mathrm{gm}$ of Nitrogen $\left(\mathrm{N}_{2}\right)$ gas is kept at a temperature $30^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$ pressure. At constant pressure some amount of heat is supplied to the system and its temperature become $35 \mathrm{C}$. After that again starting from initial state its volume changes same as the first case in isothermal process. $\left(\mathrm{R}=8.31 \mathrm{Jmol}^{-1} \mathrm{~K}^{-1}, \mathrm{C}_{\mathrm{v}}=8.31 \mathrm{Jmol}^{-1} \mathrm{~K}^{-1}\right)$.

Rajshahi Board-2023
ব্যাখ্যা আনলক করতে চর্চা প্রিমিয়াম এ আপগ্রেড করো