NEET Physics MCQs

A protein molecule's diameter is measured as 42 Å using X-ray diffraction. If another measurement instrument gives the diameter in picometers (pm), and the ratio of the two measurements is $\frac{x}{10}$, what is the value of $x$?

100 cm is equivalent to how many kilometers?

The wavelength $\lambda$ of matter waves is given by $\lambda = \frac{h}{p}$, where $h$ is Planck's constant and $p$ is momentum. If a new quantity $Z$ is defined as $Z = \frac{h^2}{\lambda^2 p c}$, where $c$ is the speed of light, the dimensions of $Z$ are:

A body travels along a path described by $y = x^2$. What is the ratio of distance to displacement when moving from $(0,0)$ to $(2,4)$?

The wavelength of a light wave is 500 nm. Express this wavelength in meters.

Two simple pendulums, A and B, have lengths $l$ and $4l$ respectively. If the time period of pendulum A is T, what is the time period of pendulum B?

A simple pendulum completes 20 oscillations in 40 seconds. If the length is doubled, what is the new time period?

A potentiometer wire of length L and resistance R is connected to a driver cell of negligible internal resistance and emf E. A cell of emf E/2 is balanced at a length L/2. If the length of the potentiometer wire is doubled, at what length will the same cell be balanced?

In a potentiometer experiment, the balancing length for a cell is found to be $l$. If the driver cell is replaced by another cell of double the emf, what will be the new balancing length, assuming all other parameters remain constant?

A potentiometer is being used to compare two cells of emfs $E_1$ and $E_2$. The balancing lengths are found to be $l_1$ and $l_2$ respectively. If a resistance R is connected across $E_2$, its balancing length changes to $l_3$. Which of the following relations must hold true?