Question
An extremely hot star would appear to be
|
(a) Red |
(b) Blue |
(c) Yellow |
(d) Orange |
✓
Answer
(b) Blue
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Similar questions
Some electric bulbs are connected in series across a 220 V supply in a room. If one bulb is fused then remaining bulbs are connected again in series across the same supply. The illumination in the room will
|
(a) Increase |
(b) Decrease |
(c) Remains the same |
(d) Not continuous |
Two short magnets of equal dipole moments M are fastened perpendicularly at their centre (figure). The magnitude of the magnetic field at a distance d from the centre on the bisector of the right angle is: 
→ - $\frac{\mu_0}{4\pi}\frac{\text{m}}{\text{d}^3}$
- $\frac{\mu_0}{4\pi}\frac{\sqrt{2}\text{M}}{\text{d}^3}$
- $\frac{\mu_0}{4\pi}\frac{\sqrt[2]{2}\text{M}}{\text{d}^3}$
-
$\frac{\mu_0}{4\pi}\frac{2\text{M}}{\text{d}^3}$
Two projectiles A and B are projected with angle of projection 15° for the projectile A and 45° for the projectile B. If RA and RB be the horizontal range for the two projectiles, then:
- RA < RB
- RA = RB
- RA > RB
- The information is insufficient to decide the relation of RA with RB.
Complete the reaction:
86Rn220→84Po216+ __________:
86Rn220→84Po216+ __________:
In the circuit, the potential difference across PQ will be nearest to
|
(a) 9.6 V |
(b) 6.6 V |
(c) 4.8 V |
(d) 3.2 V |
Two particle of mass m and 2m moving in opposite direction collide head on. They have same de-Broglie wavelength before collision after the collision.
The current sensitivity of a moving coil galvanometer can be increased by
|
(a) Increasing the magnetic field of the permanent magnet |
|
(b) Increasing the area of the deflecting coil |
|
(c) Increasing the number of turns in the coil |
|
(d) a, b, c |
An electron is revolving round a proton, producing a magnetic field of 16 weber/m2 in a circular orbit of radius 1Å. It’s angular velocity will be
|
(a) 1017 rad/sec |
(b) 1/2 π × 1012 rad/sec |
|
(c) 2π × 1012 rad/sec |
(d) 4 π × 1012 rad/sec |
1 Pico farad =
Coulomb force and gravitational force follows the: