When plate voltage in diode valve is increased from 100V to 150V. Then, plate increases from 7.5 mA to 12 mA, then dynamic plate resistance will be

• 10 kΩ

• 11 kΩ

• 15 kΩ

• 11.1 kΩ

Find equivalent resistance between X and Y

• R

• R/L

• 2R

• 5R

73.

A engine pumps up 100 kg of water through a height of 10 m in 5s. Given that, the efficiency of engine is 60%. If g = 10 ms^-2, the power of this engine is

• 3.3 kW

• 0.33 kW

• 0.033 kW

• 33 kW

A wire of resistance 10Ω is bent to form a complete circle. Find its resistance between two diametrically opposite point.

• 5 Ω

• 2.5 Ω

• 1.25 Ω

• $\frac{10}{3}$ Ω

Find the resistance of a hollow cylindrical conductor of length 1.0 mm and 2.0 mm respectively. The resistivity of the material is 2.0 × 10^-8 Ωm

• 2.1 × 10^-3 Ω

• 1.3 × 10^-4 Ω

• 3.2 × 10^-4 Ω

• 4.6 × 10^-2 Ω

The ammeter shown in figure consists of a 480 Ω coil connected in parallel to a 20 Ω shunt. The reading of ammeter is

• 0.125 A

• 1.67 A

• 0.13 A

• 0.67 A

A copper rod of length 20 cm and cross-sectional area 2 mm is joined with a similar aluminium rod as shown below

The resistance of pair of rods is (ρ_Al =2.6 x 10^-8 Ω-m and  ρ_Cu =1.7 x 10^-8 Ω-m)

• 1.0 mΩ

• 2.0 mΩ

• 3.0 mΩ

• None of these

The electron of H - atom is revolving around the nucleus in circular orbit having radius $\frac{{\mathrm{h}}^2}{4\mathrm{\pi } {\mathrm{me}}^2}$ with $\left(\frac{2\mathrm{\pi } {\mathrm{e}}^2}{\mathrm{h}}\right)$. The current produced due to the motion of electron is

• $\frac{2\mathrm{\pi } {\mathrm{m}}^2 {\mathrm{e}}^2}{3{\mathrm{h}}^2}$

• zero

• $\frac{2 {\mathrm{\pi }}^2 \mathrm{me}}{{\mathrm{h}}^2}$

• $\frac{4{\mathrm{\pi }}^2 {\mathrm{me}}^5}{{\mathrm{h}}^3}$

The galvanometer resistance is 30 Ω and it is connected to 2 V battery along with a resistance 2000 Ω in series. A full scale deflection of 25 divisions is obtained. In order to reduce this deflection to 20 divisions, the resistance in series should be

• 2470 Ω

• 2370 Ω

• 2180 Ω

• 2210 Ω

In the given figure, potential difference between A and B is

• 0 V

• 5 V

• 10 V

• 15 V