Length of a hollow tube is 5 m, its outer diameter is 10 cm and thickness of its wall is 5 mm. If resistivity of the material of the tube is 1.7 x 10⁻⁸ Ωm, then the resistance of the tube will be
(a) 5.6 × 10⁻⁵ Ω
(b) 2 × 10⁻⁵ Ω
(c) 4 × 10⁻⁵ Ω
(d) None of these
(a) 5.6 × 10⁻⁵ Ω
(b) 2 × 10⁻⁵ Ω
(c) 4 × 10⁻⁵ Ω
(d) None of these
(a) 5.6 × 10⁻⁵ Ω
A network of resistors is connected to a 16 V battery with internal resistance of 1Ω as shown in the Fig. Compute the equivalent resistance of the network.
(a) 5 ohm
(b) 7 ohm
(c) 9 ohm
(d) 10 ohm
A new flashlight cell of emf 1.5 volts gives a current of 15 amps, when connected directly to an ammeter of resistance 0.04 Ω. The internal resistance of cell is
(a) 0.04 Ω
(b) 0.06 Ω
(c) 0.10 Ω
(d) 10 Ω
A Daniel cell is balanced on 125 cm length of a potentiometer wire. When the cell is short circuited with a 2 Ω resistance, the balancing length obtained is 100 cm. Internal resistance of the cell will be
(a) 1.5 Ω
(b) 0.5 Ω
(c) 1.25 Ω
(d) 4/5 Ω
A battery of emf 10 V and internal resistance 3 ohm is connected to a resistor. If the current in the circuit is 0.5 A, find :
(i) the resistance of the resistor;
(ii) the terminal voltage of the battery.
A torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The emf of the cell needed to make the bulb glow at full intensity is
(a) 4.5 V
(b) 1.5 V
(c) 2.67 V
(d) 13.5 V
In meter bridge, the balancing length from left end when standard resistance of 1 Ω is in right gap is found to be 20 cm. The value of unknown resistance is
(a) 0.25 Ω
(b) 0.4 Ω
(c) 0.5 Ω
(d) 4 Ω
Five resistances are combined according to the figure. The equivalent resistances between the points X and Y will be
(a) 10 Ω
(b) 22 Ω
(c) 20 Ω
(d) 50 Ω
A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity ω about an axis at right angle to uniform magnetic field B. The induced emf in the coil will be
(a) NBAsinωt
(b) NBωsinωt
(c) NB/Asinωt
(d) NBAωsinωt
To observe diffraction, the size of the obstacle
(a) should be X/2, where X is the wavelength.
(b) should be of the order of wavelength.
(c) has no relation to wavelength.
(d) should be much larger than the wavelength.
The fringe width (β) of a diffraction pattern and the slit width d are related as:
(a) β ∝ d
(b) β ∝1/d
(c) β ∝ √d
(d) β ∝ 1/\(d^2\)
In Young’s double slit experiment the distance between the slit and the screen is doubled and the separation between the slit is reduced to half. The fringe width:
(a) is doubled
(b) become four time
(c) is halved
(d) remain unchanged
A tiny spherical oil drop carrying a net charge q is balanced in still air with a vertical uniform electric field strength 81/7 x 10⁵ Vm⁻¹. When the field is switched off, the drop is observed to fall with terminal velocity 2 x 10⁻³ ms⁻¹, given g = 9.8 ms⁻², viscosity of the air = 1.8 x 10⁻⁵ Nsm⁻², and the density of oil = 900 kgm⁻¹. The magnitude of q is.
(A) 1.6 x 10⁻¹⁹ C
(B) 3.2 x 10⁻¹⁹ C
(C) 4.0 x 10⁻¹⁹ C
(D) 8.0 x 10⁻¹⁹ C
Three charges each equal to 2 μC are placed at the corners of an equilateral triangle. If force between any two charges is 2F, then the net force on either will be:
Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²