List of top Questions asked in EAMCET- 2012

A long curved conductor carries a current $I$ (I is a vector). A small current element of length $d l$, on the wire induces a magnetic field at a point, away from the current element. If the position vector between the current element and the point is $r$, making an angle with current element then, the induced magnetic field density; $d B$ (vector) at the point is $\left(\mu_{0}=\right.$ permeability of free space $)$

A proton when accelerated through a potential difference of $V$, has a de-Broglie wavelength $\lambda$ associated with it. If an $\alpha$ -particle is to have the same de-Broglie wavelength $\lambda$, it must be accelerated through a potential difference of

The half-life of a radioactive element is $10 \,h$. The fraction of initial radioactivity of the element that will remain after $40\, h$ is

A primary coil and secondary coil are placed close to each other. A current, which changes at the rate of 25 A in a millisecond, is present in the primary coil. If the mutual inductance is $92 \times 10^{-6} H$, then the value of induced emf in the secondary coil is

Total emf produced in a thermocouple does not depend on

The half-life of $Ra ^{226}$ is 1620 years. Then the number of atoms decay in one second in $1 g$ of radium (Avogadro number $\left.=6.023 \times 10^{23}\right)$

Two small spheres each having equal positive charge $Q$ (Coulomb) on each are suspended by two insulating strings of equal length $L$ (metre) from a rigid hook (shown in figure). The whole set up is taken into satellite where there is no gravity. The two balls are now held by electrostatic forces in horizontal position, the tension in each string is then 

The de-Broglie wavelength of an electron moving with a velocity of $1.5 \times 10^{8} m / s$ is equal to that of a photon. The ratio of kinetic energy of the electron to that of the photon $\left(c=3 \times 10^{8} m / s \right)$