NEET 2016

Electrons of mass m with de-Broglie wave length $$\lambda$$ fall on the target in an X-ray tube. The cutoff wavelength $$(\lambda_0)$$ of the emitted X-ray is

Photons with energy 5eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is

If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength $$\lambda$$. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be

The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is

For CE transistor amplifier, the audio signal voltage across the collector resistance of $$2kΩ$$ is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is $$1kΩ$$, then the input signal voltage is

The given circuit has two ideal diodes connected as shown in the figure below. The current flowing through the resistance $$R_1$$, will be

What is the output Y in the following circuit, when all the three inputs A, B, C are first O and then 1?

Planck’s constant (h), speed of light in vacuum (c) and Newton’s gravitational constant (G) are three fundamental constants. Which of the following combinations of these has the dimension of length ?

Two cars P and Q start from a point at the same time in a straight line and their positions are represented by $$x_P(t)=at+bt^2$$ and $$x_Q(t)=ft-t^2$$. At what time do the cars have the same velocity?

In the given figure, $$a=15 \frac{m}{s^2}$$ represents the total acceleration of a particle moving in the clockwise direction in a circle of radius R=2.5 m at a given instant of time. The speed of the particle is