41.

The output of a step down transformers is measured to be 48 V when connected to a 12 W bulb. The value of peak current is

• $\frac{1}{2\sqrt{2}} \mathrm{A}$

• $\frac{1}{4} \mathrm{A}$

The particle emitted in the decay of ${}_{92}{}^{238}\mathrm{U}$ to ${}_{92}{}^{238}\mathrm{U}$

• 2 α and 2β

• 1 α and 1 β

• 1 α only

• 1 α and 2 β

From the following graph of photo current against collector plate potential, for two different intensities of light I₁ and I₂, one can conclude

• I₁ = I₂

• I₁ > I₂

• I₁ < I₂

• Comparision is not possible

In the three parts of a transistor, 'Emitter' is of

• larger size and lightly doped

• moderate size and heavily doped

• thin size and heavily doped

• large size and moderately doped

A basic communication system consists of

1. Transmitter
2. Information sources
3. User of information
4. Channel
5. Receiver

• ii, i, iv, v and iii

• i, ii, iii, iv and v

• ii, v, i, iv and iii

• ii, iv, i, iii and v

According to Huygens' principle, during refraction of light from air to a denser medium

• Wavelength decreases but speed increases

• Wavelength increases but speed decreases

• Wavelength and speed increases

• Wavelength and speed decreases

The mass defect of ${}_2{}^4\mathrm{He}$ is 0.03 u. The binding energy per nucleon of helium (in MeV) is

• 6.9825

• 27.93

• 2.793

• 69.825

According to cartesian sign convention, in ray optics

• all distance are taken negative

• all distances in the direction of incident ray are taken positive

• all distances are taken positive

• al distances in the direction of incident ray are taken negative

A linear object of height 10 cm is kept in front of a concave mirror of radius of curvature 15 cm, at a distance of 10 cm. The image formed is

• magnified and erect

• magnified and inverted

• diminished and erect

• diminished and inverted

The energy gap in case of which of the following is less than 3 eV ?

• Germanium

• Iron

• Copper

• Aluminium