Practice Questions

Q29.A ray of light passing through a prism (μ incidence is double the angle of refraction within the prism. Then, the angle of prism is (in degrees).

Q29.A circuit is arranged as shown in figure. The output voltage Vo is equal to __________ V.

Q29.In a semiconductor, the number density of intrinsic charge carriers at 27°C is 1. 5 × 1016 m−3 . If the semiconductor is doped with an impurity atom, the hole density increases to 4. 5 × 1022 m−3 . The electron density in the doped semiconductor is _______ ×109 m−3

Q29.The voltage across the 10 Ω resistor in the given circuit is x volt. The value of x to the nearest integer is _____.

Q29.A zener diode having zener voltage 8 V and power dissipation rating of 0. 5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance Rp is _____ Ω.

Q29.An inductor of 10 mH is connected to a 20 V battery through a resistor of 10 kΩ and a switch. After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after 𝑥 1 μs is mA. Then 𝑥 is equal to ______ . (Take 𝑒-1 = 0 . 37) 100

Q29.The value of power dissipated across the zener diode (Vz = 15 V) connected in the circuit as shown in the figure is x × 10−1 W. The value of x to the nearest integer is _______.

Q29.An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2. 25 from vacuum. The wavelength of this wave in that medium will be _________ ×10−2 cm.

Q29.The circuit contains two diodes each with a forward resistance of 50 Ω and with infinite reverse resistance. If the battery voltage is 6 V , the current through the 120 Ω resistance is _______ mA

Q29.The Kα X-ray of molybdenum has wavelength 0. 071 nm. If the energy of a molybdenum atom with a K electron knocked out is 27. 5 keV, the energy of this atom when an L electron is knocked out will be keV. (Round off to the nearest integer ) [h = 4. 14 × 10−15 eV s, c = 3 × 108 m s−1]

Q29.The energy dissipated by a resistor is 10 mJ in 1 s, when an electric current of 2 mA flows through it. The resistance is ________ Ω. (Round off to the Nearest Integer)

Q29.White light is passed through a double slit and interference is observed on a screen 1. 5 m away. The separation between the slits is 0. 3 mm . The first violet and red fringes are formed 2. 0 mm and 3. 5 mm away from the central white fringes. The difference in wavelengths of red and violet light is (in nm).

Q29.A bandwidth of 6 MHz is available for 𝐴. 𝑀. transmission. If the maximum audio signal frequency used for modulating the carrier wave is not to exceed 6 kHz . The number of stations that can be broadcasted within this band simultaneously without interfering with each other will be __________. JEE Main 2021 (31 Aug Shift 2) JEE Main Previous Year Paper

Q29.A source of light is placed in front of a screen. The intensity of light on the screen is I . Two Polaroids P1 and P2 are so placed in between the source of light and screen that the intensity of light on the screen is I2 . Then the P2 , should be rotated by an angle of (degrees) so that the intensity of light on the screen becomes 3I8 .

Q29.The image of an object placed in air formed by a convex refracting surface is at a distance of 10 m behind the surface. The image is real and is at 2rd of the distance of the object from the surface. The wavelength of light 3 inside the surface is 2 times the wavelength in air. The radius of the curved surface is x m , the value of x 3 13 is ______ .

Q30.For VHF signal broadcasting, _______ km2 of maximum service area will be covered by an antenna tower of height 30 m, if the receiving antenna is placed at ground. Let radius of the earth be 6400 km. (Round off to the Nearest Integer) (Take π as 3. 14 )

Q30.The amplitude of upper and lower side bands of AM wave where a carrier signal with frequency 11. 21 MHz, peak voltage 15 V is amplitude modulated by a 7. 7 kHz sine wave of 5 V amplitude are 10a V and 10b V respectively. Then the value of a is_____. b JEE Main 2021 (27 Jul Shift 1) JEE Main Previous Year Paper

Q30.If the sum of the heights of transmitting and receiving antennas in the line of sight of communication is fixed at 160 m, then the maximum range of LOS communication is _______ km (Take radius of Earth = 6400 km)

Q30.The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is

Q30.The diameter of a spherical bob is measured using a vernier callipers. 9 divisions of the main scale, in the vernier callipers, are equal to 10 divisions of vernier scale. One main scale division is 1 mm . The main scale reading is 10 mm and 8th division of vernier scale was found to coincide exactly with one of the main scale division. If the given vernier callipers has positive zero error of 0 . 04 cm, then the radius of the bob is _____________ × 10-2 cm .

Q30.A zener diode of power rating 2 W is to be used as a voltage regulator. If the zener diode has a breakdown of 10 V and it has to regulate voltage fluctuated between 6 V and 14 V , the value of Rs for safe operation should be _____ Ω .

Q30.The wavelength of an X-ray beam is 10 Å . The mass of a fictitious particle having the same energy as that of the X-ray photons is x h kg. The value of x is ___ . ( h =Planck's constant) 3

Q30.An audio signal 𝑣𝑚= 20sin2𝜋1500𝑡 amplitude modulates a carrier 𝑣𝑐= 80sin2𝜋100, 000𝑡. The value of percent modulation is

Q30.For the forward biased diode characteristics shown in the figure, the dynamic resistance at ID = 3 mA will be ________ Ω. JEE Main 2021 (20 Jul Shift 2) JEE Main Previous Year Paper

Q30.In the logic circuit shown in the figure, if input A and B are 0 to 1 respectively, the output at Y would be x. The value of x is _________.