Physics

A double convex lens is made of glass which has its refractive index of 1.55 for violet rays and 1.50 for red rays. If the focal length for violet rays is 20cm, then the focal length for red rays will be cm.

The torque $\stackrel{?}{\tau }$ acts on a body about a given point is found to be equal to $\stackrel{?}{A}*\stackrel{?}{L}$ where $\stackrel{?}{A}$ is a constant nonzero vector and $\stackrel{?}{L}$ is the angular momentum of the body about that point. Choose the incorrect option: $(\stackrel{?}{A}\ne \pm \hat{L})$

A beam of unpolarized light of intensity I? is incident on a polaroid A. Then it is passed through another polaroid B. If the intensity of the emergent light is 18% of the original unpolarized light then find the angle (nearest integer in degree) between the principal plane of polaroid A and B.

In the given circuit find the current through the Zener diode in mA.

A particle of mass 3 kg moving with speed of 3 m/s is acted upon by an impulse. As a result, the particle starts moving in a direction 90° to the original direction with a speed of 4 m/s. Find the impulse acted upon on the particle in SI units.

An inductor of inductance 0.1H and a resistor of resistance 8Ω are connected in series to a battery of emf 1.5 V through a switch. Find the initial rate of growth of current when the switch is closed (in A/s).

Speed of sound in a resonance tube experiment is given by the expression v = 2f₀(l₂ – l₁) where f? is the frequency of the tuning fork and l₁, l₂ are length of the air column. Consider f₀ = 300 Hz with no error in its value. Lengths of the air column l₁ and l₂ are measured as 25.0 cm and 80.0 cm respectively. Find the absolute error in the speed of sound (in m/s).

A capacitor of capacitance 3µF is charged to a potential difference of 12V. Another identical capacitor, initially uncharged is filled with a dielectric having dielectric constant K and it is connected to the charged capacitor. The final common potential difference across both capacitors is found to be 2V. Find the value of k.

A wooden wheel having radius of 1 m is to be fitted with an iron ring around it. The diameter of the ring is 6 mm smaller than the wooden wheel. If the coefficient of linear expansion of iron is 1.2 * 10^-5/ °C, then find the minimum increase in temperature (in °C) to fit the ring on the wheel.

A bucket of height 20 cm is placed under a tap such that water flows into the bucket at a constant rate of 100 cm³/s. There is a small hole in the bucket of cross-sectional area of 1 cm² at height of 3 cm from the bottom. Area of hole is very small as compared to area of the bucket. Find the maximum height (in cm ) above the bottom upto which the water is filled in the bucket. (Take g = 10 m/s² )