Physics Test - ...

The displacement y of a particle executing periodical motion is given by y = 4 cos² (t/2) sin (1000t). This expression may be considered to be a result of the superposition of how many independent harmonic motions?

Three particles, each of mass $\text{'}m\text{'}g$, are situated at the vertices of an equilateral triangle $ABC$ of side $lcm$ (as shown in the figure). The moment of inertia of the system about a line $AX$ perpendicular to $AB$ in the plane of $ABC$ in gram-$c{m}^2$ unit will be:

In an LCR series circuit, the potential difference between the terminals of the inductance is $60V$, that between the terminals of the capacitor is $30V$ and that across the resistance is $40V$. Then, the supply voltage will be:

A steel wire of length $\text{'}l\text{'}$ has a magnetic moment $M$. It is bent into a semicircular arc. The new magnetic moment is:

Two weights $\text{'}{w}_1\text{'}$ and $\text{'}{w}_2\text{'}$ are suspended by two strings on a frictionless pulley. When the pulley is pulled up with an acceleration $\text{'}g\text{'}$, then the tension in the string is:

A stone is dropped from a certain height which can reach the ground in \(5\) seconds. If the stone is stopped after \(3\) seconds of its fall and then allowed to fall again, then the time taken by the stone to reach the ground for the remaining distance is-

The binding energies for nuclei ${}_{1}H^1,{}_{2}H{e}^4,{}_{26}F{e}^{56}$ and ${}_{92}U^{235}$ are $2.22,28.3,492$ and $17.86MeV$, respectively. The most stable nucleus is:

$F_1$ and $F_2$ are focal lengths of the objective and the eyepiece of a telescope, respectively. The angular magnification for this telescope is equal to:

A horizontal platform is rotating with a uniform angular velocity around the vertical axis passing through its centre. At some instant in time, viscous fluid of mass $\text{'}m\text{'}$ is dropped at the centre and is allowed to spread out and finally fall. The angular velocity during this period:

For a certain radioactive substance, it is observed that after $4$ hours, only $6.25\%$ of the original sample is left undecayed. Which of the following statements is incorrect?