List of practice Questions

When a metallic surface is illuminated with radiation of wavelength $\lambda$ , the stopping potential is V. If the same surface is illuminated with radiation of wavelength $2 \lambda$, the stopping potential is $\frac{V}{4}$ . The threshold wavelength for the metallic surface is :

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

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

DNA-dependent RNA polymerase catalyzes transcription on one strand of the DNA which is called the

Cortex is the region found between -

Consider the junction diode as ideal. The value of current flowing through \(AB\) is :

Boric acid is an acid because its molecule

An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is :

An electric dipole is placed at an angle of $30^{\circ}$ with an electric field intensity $2 \times 10^{5} N / C .$ It experiences a torque equal to $4\, Nm$. The charge on the dipole, if the dipole length is $2\, cm$, is

A rectangular film of liquid is extended from $(4 \, cm \times 2\, cm)$ to $ (5 \, cm \times 4 \, cm)$. If the work done is $3 \times 10^{-4} \, J$, the value of the surface tension of the liquid is -

A $n-p-n$ transistor is connected to common emitter configuration in a given amplifier. A load resistance of $800$ is connected in the collector circuit and the voltage drop across it is $0.8\, V$. If the current amplification factor is $0.96$ and the input resistance of the circuit is $192\,\Omega$, the voltage gain and the power gain of the amplifier will respectively be

A molecule that can act as a genetic material must fulfill the traits given below, except

The electronic configurations of Eu (Atomic No. 63), Gd(Atomic No. 64) and Tb (Atomic No. 65) are:

The reaction can be classified as:

Water soluble pigments found in plant cell vacuoles are -

Which of the following features is not present in Periplaneta americana ?

A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by $60^{\circ}$ is $W$. Now the torque required to keep the magnet in this new position is

Which of the following is correct for r-selected species ?

Which of the following is incorrect regarding vasectomy ?

Which of the following is not a stem modification?

Which of the following is the correct sequence of events in the origin of life ? I. Formation of protobionts II. Synthesis of organic monomers III. Synthesis of organic polymers IV. Formation of DNA-based genetic systems

Which of the following most appropriately describes haemophilia ?

Which of the following National Parks is home to the famous musk deer or hangul ?

Which of the following pairs of d-orbitals will have electron density along the axes?

Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other ?