List of top Physics Questions asked in AP ECET

A solid copper sphere of density $\rho$, specific heat capacity $C$ and radius $r$ is initially at $200\, K$. It is suspended inside a chamber whose walls are at $0\, K$. The time required (in (is) for the temperature of the sphere to drop to $100 \,K$ is ($\sigma$ is Stefan's constant and all the quantities are in SI units)

A parallel plate capacitor consists of two circular plates each of radius $2 \,cm$, separated by a distance of $0.1 \,mm$. If the potential difference across the plates is varying at the rate of $5 \times 10^{6} Vs ^{-1}$, then the value of displacement current is

A proton and an $\alpha$-particle are simultaneously projected in opposite directions into a region of uniform magnetic field of $2\, mT$ perpendicular to the direction of the field. After some time it is found that the velocity of proton has changed in direction by $90^{\circ}$. Then at this tune, the angle between the velocity vectors of proton and $\alpha$ - particle is

A point charge $q$ is placed at origin. Let $E _{A^{\prime}} E _{B}$ and $E _{C}$ be the electric fields at three points $A$ $(1,2,3), B(1,1,-1)$ and $C(2,2,2)$ respectively due to the charge $q$. Then, the relation between them is 1. $E _{A} \perp E _{B}$ 2. $E _{A} \| E _{C}$ 3. $\left| E _{B}\right|=4\left| E _{c}\right|$ 4. $\left| E _{B}\right|=8\left| E _{c}\right|$

Wires $ A $ and $ B $ have resistivities $ \rho_{A} $ and $ \rho_{B} $ , $ (\rho_{B}=2\rho_{A}) $ and have lengths $ l_{A} $ and $ l_{B} $ . If the diameter of the wire $ B $ is twice that of $ A $ and the two wires have same resistance, then $ \frac{l_{B}}{l_{4}} $ is

A convex lens has its radii of curvature equal. The focal length of the lens is $f$. If it is divided vertically into two identical plano-convex lenses by cutting it, then the focal length of the plano-convex lens is $(\mu=$ the refractive index of the material of the lens $)$

A thin converging lens of focal length $ f = 25\, cm $ forms the image of an object on a screen placed at a distance of $ 75\, cm $ from the lens. The screen is moved closer to the lens by a distance of $ 25\, cm $ . The distance through which the object has to be shifted, so that its image on the screen in sharp again is

Three resistances of equal values are arranged in four different configurations as shown below. Power dissipation in the increasing order is

Four resistors $A, B, C$ and $D$ form a Wheatstones bridge. The bridge is balanced, when $C=100 \Omega$. If $A$ and $B$ are interchanged, the bridge balances for $C=121 \Omega$. The value of $D$ is

Three rods of same dimensions have thermal conductivities 3 K, 2 K and K. They are arranged as shown below:What will be the temperature T of the junction?

A ball of mass 0.6 kg attached to a light inextensible string rotates in a vertical circle of radius 0.75 m such that it has a speed of $ 5\text{ }m{{s}^{-1}} $ when the string is horizontal. Tension in string when it h horizontal on other side is $ (g=10m{{s}^{-}}2) $

Of the vectors given below, the parallel vectors are, $ A = 6 \hat i + 8 \hat j$ $30mm B = 210 \hat i + 280 \hat k$ $ C = 0.3 \hat i + 0.4 \hat j$ $ D = 3.6 \hat i + 6 \hat j + 4.8 \hat k$