Which of the following pairs of ions have the same paramagnetic moment?

Two resistances of $400\,\Omega$ and $800\,\Omega$ are connected in series with a $6\,V$ battery of negligible internal resistance. $A$ voltmeter of resistance $10,000\,\Omega$ is used to measure the potential difference across the $400\,\Omega$ resistor. The error in the measurement of potential difference (in volts) is approximately:

The coils of a step-down transformer have $500$ and $5000$ turns. In the primary coil,an $AC$ of $4 \, A$ at $2200 \, V$ is sent. The value of the current and potential difference in the secondary coil will be:

The two curves $x=y^2$ and $xy=a^3$ cut orthogonally at a point, then $a^2$ is equal to

If the wavelength of an electromagnetic radiation is $2000 \ \mathring{A}$,what is its energy in ergs?

An object $1\;cm$ tall is placed $4\;cm$ in front of a mirror. In order to produce an upright image of $3\;cm$ height,one needs a: